ESE's works engine tuner

[kanjeneroo]

Hello everyone,

i read that you can cut out a little bit on the bottem of the intake side of the piston, so that the front intake opens faster.
i understand that when the piston is at TDC and the front intake is uncovered a bit , you can make it larger so that it opens more.

now when i look at my piston at TDC, my vertex piston blocks 100% of the intake port. now my question is, what happens to my 'engine fluids' when i do make a hole or someting so that at TBC the front intake is open ?


another question :) I saw that when the piston is rising to TDC, a certain time the booster exhaust ports are connected to each other by the piston pin. is that ideal ? or is a closed piston pin better fot that ? also when the piston pin crosses the tranfer ports you have a connestion between them, normal ? good ? or bad ?


kind regards,
Jonathan

[ief]

Have you got a way to see if the crank still is 'trued' after all that muckin about with it adegnes?

I like the vids as well but... I'm more fond of videos explaining thing from A to Z. Like how you balance, measure, why, how etc.

Curious to see what your angle grinder idea is :)

[adegnes]

Have you got a way to see if the crank still is 'trued' after all that muckin about with it adegnes?

I like the vids as well but... I'm more fond of videos explaining thing from A to Z. Like how you balance, measure, why, how etc.

Curious to see what your angle grinder idea is :)

Thanks!

I made a simple knife edge jig to check the trueness some years back, but since I can't find it I'll make a new one on camera.

I too like the a-z how to's, and I want to do more of those(hoping they don't turn out as "how not to's"...)

I've said this before, and I know it's my own fault, but I don't want to take up too much "space" in this thread, you can leave feedback directly in the comments of the videos too.
I really appreciate your input, just don't want it to become too much.
If it's no problem, it's no problem, if it is, please let me know!

[Frits Overmars]

...one of the spark plugs had only been in contact with an open ended wrench....That may not break the pocelain but it can very well cause an different problem. An open ended wrench bears on just two points of the hexagon and as the spark plug body is relatively thin-walled, you'll risk pushing the hexagon out of round, causing leakage at the top seal between the hexagon and the porcelain.


Hello everyone, i read that you can cut out a little bit on the bottem of the intake side of the piston, so that the front intake opens faster. i understand that when the piston is at TDC and the front intake is uncovered a bit , you can make it larger so that it opens more. now when i look at my piston at TDC, my vertex piston blocks 100% of the intake port. now my question is, what happens to my 'engine fluids' when i do make a hole or someting so that at TBC the front intake is open ?
another question: I saw that when the piston is rising to TDC, a certain time the booster exhaust ports are connected to each other by the piston pin. is that ideal ? or is a closed piston pin better fot that ? also when the piston pin crosses the tranfer ports you have a connestion between them, normal ? good ? or bad ?
kind regards, JonathanHi Jonathan. As far as I know, the intake of a KZ10B is always open and by the time the inlet starts flowing, the piston is already on its way up, getting out of the flow path. At TDC the piston is well and truly out of the way.
I've shortened the inlet side of kart pistons myself, but that was a reliability issue rather than a hunt for power, because sometimes the bottom lips of the piston skirt would break off, so I decided I'd better remove them myself before they could start wandering through the engine.
By the way, I happen to know that you're talking about a 125 cc TM kart engine, but not everybody here will, so try to be as clear as possible about these things.
And while you're at it, a brief introduction of your good self would be welcome (assuming you haven't already done that in another thread, in which case it's my bad).

There is no problem when the auxiliary exhaust portst are interconnected via the open piston pin because there is no pressure difference between them, so there will be no flow. And the same is true when the piston pin connects the tranfer ports with each other.
But in-between these two situations there can be a problem, when the pin bores of the piston (the yellow circle in the picture below-left) connect the auxiliary exhaust ports with the transfer ports underneath them. This either limits the size of the auxiliary exhaust ports, or it necessitates plugging the pin bores (picture below-right) so that they are flush with the piston skirt as much as possible. Here you can also see that chamfered pin bores, while facilitating pin fitting, worsen leakage.
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[Tim Ey]

Talking kart pistons:

Has anyone a hint on a very good 54mm Piston:
- cast, not forged
- compression height 26mm or less
- crown radius about 120-150 (2,5mm to 3mm piston crown)
- no side cutaways on the exhaust side and minimal chambfering around the pin for minimal leakage
- 15 or 16mm pin
- single 1mm or thinner Ring
- ringpeg at 6o'clock
- long skirt
- no windows
Available till eternety, best would be from a MX :-)

Had a look at the new KTM 125SX Pistons but disliked the massive cutout on the inlet side.

Vertex 22261f?
Thanks!
Tim

[adegnes]

Now this is a first for me; luck is on my side!
I measured the balance factor after welding in the slugs, now with a properly calibrated and accurate scale.

Small end = 27,5g
Piston,pin,bearing,circlips = 81,4g
SUM Reciprocating mass = 108,9g

Weight needed to keep crank from turning = 35,4g

35,4 + 27,5 = 62,9

62,9 / 108,9 = 57,7

A little epoxy in the holes on the inside of the webs to encapsulate the slag/spatter I can't reach will raise it a tiny bit higher too.
58%ish, I'll call that close enough!

Now if only I would have checked it before uploading or posting anything!
I could have at least pretended I wasn't such a jackass... oh well, the damage is done. Frits, you are right, I would make for an awful politician...

Dodged a bullet there, with wob on his way over to give me a beating with the rum bottle and all.

[kanjeneroo]

Hi Jonathan. As far as I know, the intake of a KZ10B is always open and by the time the inlet starts flowing, the piston is already on its way up, getting out of the flow path. At TDC the piston is well and truly out of the way.
I've shortened the inlet side of kart pistons myself, but that was a reliability issue rather than a hunt for power, because sometimes the bottom lips of the piston skirt would break off, so I decided I'd better remove them myself before they could start wandering through the engine.
By the way, I happen to know that you're talking about a 125 cc TM kart engine, but not everybody here will, so try to be as clear as possible about these things.
And while you're at it, a brief introduction of your good self would be welcome (assuming you haven't already done that in another thread, in which case it's my bad).

There is no problem when the auxiliary exhaust portst are interconnected via the open piston pin because there is no pressure difference between them, so there will be no flow. And the same is true when the piston pin connects the tranfer ports with each other.
But in-between these two situations there can be a problem, when the pin bores of the piston (the yellow circle in the picture below-left) connect the auxiliary exhaust ports with the transfer ports underneath them. This either limits the size of the auxiliary exhaust ports, or it necessitates plugging the pin bores (picture below-right) so that they are flush with the piston skirt as much as possible. Here you can also see that chamfered pin bores, while facilitating pin fitting, worsen leakage.
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Thx for the reply. I meant the intake front port in the cylinder. Between the tranfser ports.

[wobbly]

The KZ10B piston skirt does close off completely the boost port exit at TDC, but I have narrowed and shortened a piston skirt
thinking that it would help intake flow at BDC - sorry no free lunch.
At BDC there is no intake flow till the piston timing edge is approaching TPC, and at TDC if the boost port is open, the other end is subjected to the same case depression
so there can be no flow.
Re port linking on this engine.
The stock setup has virtually no linking of the Aux and the A transfer by the pin hole as it passes them. Plugs in this case make NO power at all.
But widen the Aux top edge around to bore center, extending the teardrop shape along with a good angled/radiused back corner, and huge gains in peak and overev power suddenly appear.
This is at the expense of around 2 to 3 Hp at 10,000 - drivers hate this even if the lap times are well faster.
My feeling is that if the transfers were left stock and the main/aux Ex port were lowered with this mod that increases blowdown flow, good gains would be had everywhere.
Plug the pin and you get most of the bottom end back, but this mod has little effect approaching and past peak power.
Trouble is I have tried several variations of "plastic " plugs that use the clip for retention, and discovered that this limits the lubrication of the pin in the piston.
The pin ends up getting locally overheated.It never actually failed on me in use, but I now see the value in why Jan used Pankle at great expense to weld a thin plate
over the pin end on his Aprilia.
Also here is what happens if the plug is too close to the bore - one National title of the last 4 gone up in smoke.

[kanjeneroo]

They have closed full metal pins, so no more problem of no lubrication caused to those plugs 😀

Can you explain what you mean by your mod on the exhaust booster ports ?

[wobbly]

Who has the closed pins - news to me ?

The important thing with the Aux ports is to get a good deep radiused pocket on the new edge close to the bore center.

[kanjeneroo]

http://mora-racing.de/TM-Engine-Parts/TM-Engine-Parts-Tav-01/23-TM-Piston-Pin::706.html

[husaberg]

http://mora-racing.de/TM-Engine-Parts/TM-Engine-Parts-Tav-01/23-TM-Piston-Pin::706.html

$248 eu, $375 NZD, $270 usd, $356 AUD.

[Hemi Makutu]

If the nylon pin plugs were centre drilled to allow a modicum of cooling flow effect, perhaps?

Has anyone tried 'golf ball' dimples on them for oil retention/anti-seizure purposes?

Or deeper, but still blind holes drilled, filled with graphite rods, semi solid moly or other anti-seize media?

Perhaps a lube slot in the conrod little end eye to match the big end for lube needs with the plugs?

A reed valve in the pin plugs?

[wobbly]

Maybe Pankle's price was cheaper,shit it couldn't have been more surely.
No matter how you do it, plastic plugs using the clip for retention wont allow flow from the transfers to impinge on the outer edge of the small end pin surface
allowing lube into the pistons gudgeon hole bearing area.
Additional holes drilled upward from below the pistons gudgeon boss may help, but the TM pistons are pretty thin in this area.
The gains are huge from generating more blowdown flow,and plugs make the mod even better, but there has to be a better/cheaper way than laser welding the pins shut.

[husaberg]

Maybe Pankle's price was cheaper,shit it couldn't have been more surely.
No matter how you do it, plastic plugs using the clip for retention wont allow flow from the transfers to impinge on the outer edge of the small end pin surface
allowing lube into the pistons gudgeon hole bearing area.
Additional holes drilled upward from below the pistons gudgeon boss may help, but the TM pistons are pretty thin in this area.
The gains are huge from generating more blowdown flow,and plugs make the mod even better, but there has to be a better/cheaper way than laser welding the pins shut.

What about using something simple like a Welch plug ie core plug freeze plug, available in brass , ss, steel etc
http://www.melling.com/Portals/0/Size%20Charts/Expansion%20Plug%20Dimensional%20Listing.pdf
http://freezeplugfactory.com/expansion-plug-size-chart/
http://www.hubbardspring.com/install_reco.php?cid=45

maybe silver soldered in?
Using a paste form filler and high temp?
they used to use it for cast iron heads etc donkeys years ago?

[adegnes]

there has to be a better/cheaper way than laser welding the pins shut.

Flux core welding the pin shut! :laugh:

Frits, did you have lubrication problems with your alien technology plastic plugs?

[wobbly]

Yep, flux core is the real deal capable of fixing any goddamn thing in a frozen over place - ive seen it on the interweb so it must be true.
Shit with all the time/effort we all put into deciphering the Ryger bullshit episode, this has to be an easy task.
One small point - we MUST have the chamfer intact on the pin end that forces the clip outward into its groove if there is any axial float in the gudgeon bore.

[Grumph]

Yep, flux core is the real deal capable of fixing any goddamn thing in a frozen over place - ive seen it on the interweb so it must be true.
Shit with all the time/effort we all put into deciphering the Ryger bullshit episode, this has to be an easy task.
One small point - we MUST have the chamfer intact on the pin end that forces the clip outward into its groove if there is any axial float in the gudgeon bore.

What about a 3 piece pin ? Normal hardened hollow center piece maybe 4mm short of the finished length. Non hardened ends pressed in - maybe the end pieces taper bored inside to save weight. The 3 pieces with enough left on the OD for a finish grind. You'd only need a very small center register for grinding - or if you have a centerless grinder that small, no center needed.
Only the area where the small end rollers run needs to be hardened of course.
Just as a normal pin, you're relying on the circlips to prevent disaster.

[kanjeneroo]

Maybe Pankle's price was cheaper,shit it couldn't have been more surely.
No matter how you do it, plastic plugs using the clip for retention wont allow flow from the transfers to impinge on the outer edge of the small end pin surface
allowing lube into the pistons gudgeon hole bearing area.
Additional holes drilled upward from below the pistons gudgeon boss may help, but the TM pistons are pretty thin in this area.
The gains are huge from generating more blowdown flow,and plugs make the mod even better, but there has to be a better/cheaper way than laser welding the pins shut.


So.your saying a closed piston pin is way better then a normal ?

[husaberg]

Yep, flux core is the real deal capable of fixing any goddamn thing in a frozen over place - ive seen it on the interweb so it must be true.
Shit with all the time/effort we all put into deciphering the Ryger bullshit episode, this has to be an easy task.
One small point - we MUST have the chamfer intact on the pin end that forces the clip outward into its groove if there is any axial float in the gudgeon bore.


I seem to remember Wob used one to balance a stator.........
Useless or maybe interesting factoid/Question
What works bike ran a aluminum alloy RR77 crankpin with a hardened sleeve. that was reliable for 9500 hard racing miles with a future multiple world champion on it when he fitted one to his production racer model?


Works Vincent grey flash
So if Al is third the density of steel why not a solid Al Gudgeon pin?

Also how did Aprilia seal the big ends?
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=314120&d=1438074128
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=302294&d=1411726997
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=303952
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=303485
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=303484
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=302294

Honda on its 4t use little press in plugs also.
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[Hemi Makutu]

What about a semi-permeable metal foam matrix?

One that transient gas flow will 'see' as solid, but will allow some liquid lubricant flow.

[wobbly]

Aprilia ended up with flush laser welded end plates on the pin.
The Honda style push in cup is no good as this still allows a major connection between the Aux and the A ports as the pin passes over both of them.
YES, I am saying there is a huge advantage to be had with closed pins in tandem with wide Aux.
You can have the Aux ports around to bore center, without getting the big loss in mid power I saw without them.

And even bigger advantage is to be had in the KZ10 engine if you lower the mod Ex Blowdown STA some by using the wide Aux but then reducing the timings.
Also the KZ10 main port is out at 72% - reduce this to closer to 68% with even wider Aux, with lower timings, and then way more power range can be gained.

But all of this is just conjecture, as rule 1A says we cant ADD material, only grind it away - unless of course the factory sees fit to manufacture cylinders this way.
When I get to work there very soon, its just one element of a raft of big mods I want to have tested to death in house.

[husaberg]

If the nylon pin plugs were centre drilled to allow a modicum of cooling flow effect, perhaps?

Has anyone tried 'golf ball' dimples on them for oil retention/anti-seizure purposes?

Or deeper, but still blind holes drilled, filled with graphite rods, semi solid moly or other anti-seize media?

Perhaps a lube slot in the conrod little end eye to match the big end for lube needs with the plugs?

A reed valve in the pin plugs?


Aprilia ended up with flush laser welded end plates on the pin.
The Honda style push in cup is no good as this still allows a major connection between the Aux and the A ports as the pin passes over both of them.
YES, I am saying there is a huge advantage to be had with closed pins, you can have the Aux ports around to bore center, without getting the big loss
in mid power I saw without them.
And even bigger advantage is to be had in the KZ10 engine if you lower the Ex Blowdown STA some by using the wide Aux but reduce the timings.
Also the KZ10 main port is out at 72% - reduce this to closer to 68% with even wider Aux, with lower timings, and even more power range can be gained.
But all of this is just conjecture, as rule 1A says we cant ADD material, only grind it away - unless of course the factory sees fit to manufacture cylinders this way.
When I get to work there very soon, its just one element of a raft of big mods I want to have tested to death in house.

With the press in plugs they just need to be used the other way arround, pretty sure a few are at least flush mount (xr200 i think) but i can't find a decent pic.
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Regardless a pressin plug can be any shape, plenty of welch plugs are domed.

[jamathi]

Aprilia ended up with flush laser welded end plates on the pin.
The Honda style push in cup is no good as this still allows a major connection between the Aux and the A ports as the pin passes over both of them.
YES, I am saying there is a huge advantage to be had with closed pins in tandem with wide Aux.
You can have the Aux ports around to bore center, without getting the big loss in mid power I saw without them.

And even bigger advantage is to be had in the KZ10 engine if you lower the mod Ex Blowdown STA some by using the wide Aux but then reducing the timings.
Also the KZ10 main port is out at 72% - reduce this to closer to 68% with even wider Aux, with lower timings, and then way more power range can be gained.

But all of this is just conjecture, as rule 1A says we cant ADD material, only grind it away - unless of course the factory sees fit to manufacture cylinders this way.
When I get to work there very soon, its just one element of a raft of big mods I want to have tested to death in house.

My very first closed piston pin test was done at Garelli, in 1988
We machined the piston pin holes outside of the bearing surface to a much bigger diameter
4-5mm bigger, and closed these with aluminium caps.
So these could never enter into the transfers!
It worked quite well and was reliable.
Power was a bit better, but not so much.
Because I left the auxiliary ports and ducts as they were, way too small...
I still had a lot to learn, which I did at Aprilia

[Tim Ey]

Shit with all the time/effort we all put into deciphering the Ryger bullshit episode, this has to be an easy task.


Weld in Caps for Pistons 54mm+ with 16mm pin and up to 1,5mm pin offset

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326132

Looks worse than it is: In a 60mm Piston the volume of the remaining space is approx 0,25cm³


To Define befor somebody calls his cousin in china to press a thousand of those
- Diameter of the cap that allows a C clip to be mount and removed
- Chambfer width needed to press the clip in position (probably done with first point)
- Lenght of the cylindric Diameter (Z) - as the position of the clip differs from piston to piston it might need a few variations of those.

cheers
Tim

[Frits Overmars]

What about using something simple like a Welch plug ie core plug freeze plug... maybe silver soldered in? Using a paste form filler and high temp?Using high temp? The temp reached by a piston pin in normal use may already melt the silver and send the plugs on an exploratory expedition through the engine.


So if Al is third the density of steel why not a solid Al Gudgeon pin? Also how did Aprilia seal the big ends?Good suggestion, except that the small end bearing needles like to have some firm (hard) surface under their feet.
But then why not go all the way and use ceramic pins? They're even lighter and much, much harder than aluminium, and not affected by temperature at all. But they still wouldn't solve the aux/transfer short circuiting. Aprilia closed their big end pins with conical plugs, but that wouldn't solve the aux/transfer short circuiting either.


What about a 3 piece pin ? Normal hardened hollow center piece maybe 4mm short of the finished length. Non hardened ends pressed in - maybe the end pieces taper bored inside to save weight. The 3 pieces with enough left on the OD for a finish grind... Just as a normal pin, you're relying on the circlips to prevent disaster.Past experience tends to point into the opposite direction: circlips can be very good at causing disaster.
And what about that 3 piece pin? Well, what about acceleration values of 5000 g around BDC and 7850 g around TDC (Aprilia RSA at its 14500 maximum rpm)?
Do you think any built-up contraption would stay together long enough under that kind of stress?


If the nylon pin plugs were centre drilled to allow a modicum of cooling flow effect, perhaps? Has anyone tried 'golf ball' dimples on them for oil retention/anti-seizure purposes? Or deeper, but still blind holes drilled, filled with graphite rods, semi solid moly or other anti-seize media? Perhaps a lube slot in the conrod little end eye to match the big end for lube needs with the plugs? A reed valve in the pin plugs?...
What about a semi-permeable metal foam matrix? One that transient gas flow will 'see' as solid, but will allow some liquid lubricant flow.I'd love to discover a material that is closed to gases and open to liquids. Might get me a Nobel price, so I could fly to Stockholm, all expenses paid, and meet Bob Dylan.


The gains are huge from generating more blowdown flow, and plugs make the mod even better, but there has to be a better/cheaper way than laser welding the pins shut....
Maybe Pankle's price was cheaper, shit it couldn't have been more surely.Then you don't know Pankl; they always live up to their reputation of being the most expensive supplier in racing.


we MUST have the chamfer intact on the pin end that forces the clip outward into its groove if there is any axial float in the gudgeon bore.You're right about that, providing you use circlips at all. That is why I did away with them and click my plugs straight into the circlip grooves.


Weld in Caps for Pistons 54mm+ with 16mm pin and up to 1,5mm pin offset. Looks worse than it is: In a 60mm Piston the volume of the remaining space is approx 0,25cm³ Tim, the issue is not the volume of the remaining space, but the cross flow area of the leakage path between auxiliary exhaust ports and transfer ports.


Frits, did you have lubrication problems with your alien technology plastic plugs?Talking about alien technology: I considered most of the ludicrous genial ideas posted above (and then some) before wising up and turning to the simplest solution I could think of: leave the circlips out (saves weight) and click the plugs directly into the circlip grooves. They will work fine in combination with a normal piston pin (saves a huge amount of money compared to a Pankl pin) and it reduces the aux/transfer leak path better then even the latest domed Pankl pin, shown in the picture below-left. Right is my simple, very light plug.

There were never any lubrication problems, only a problem when someone used plugs, designed for a Simson piston, in a Kreidler piston which has different circlip goove dimensions. One plug came out, passing through the engine without doing any harm, but then the piston pin started wandering sideways, scraping the cylinder bore.

Most of the research went into finding the proper plug material. And since I don't expect I'll ever get rich from selling plugs, I'll let the cat out of the bag:
the plugs are made of Torlon. The stuff ain't cheap, but you'll get about 20 re-usable(!) plugs for the price of one Pankl pin.

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[Grumph]

A very neat solution Frits. Are they moulded or machined ?

[Frits Overmars]

A very neat solution Frits. Are they moulded or machined ?Machined

After which www.kiwibiker.co.nz said:
The message you have entered is too short. Please lengthen your message to at least 10 characters.

So here is my new, improved answer: "Thank you Grumph; they are machined."

I wonder: why the minimum length? In other forums, when you agree with a previous remark, you can simply write: "+1". Saves a lot of keystrokes...

[F5 Dave]

Is it 4301? At least available easily enough.

http://nz.rs-online.com/web/p/plastic-rods/2577136/

[ief]

That's probably the reason why Frits ;)

[Flettner]

Is it 4301? At least available easily enough.

http://nz.rs-online.com/web/p/plastic-rods/2577136/

They don't give it away do they, that's real expensive! In anyone's book.

[Grumph]

They don't give it away do they, that's real expensive! In anyone's book.

It's expensive in my book anyway...You'd want to run the CNC programme on something cheaper a few times before you hit start on the good stuff.

Was that a broad hint that when you do them, they won't be cheap ?

[Ocean1]

They don't give it away do they, that's real expensive! In anyone's book.

I had occasion to buy some silicone filled PEEK a couple of years ago, haven't looked at current prices but it was well more than that then.

[F5 Dave]

You'd get a fair few out of that. 30 odd.

[Frits Overmars]

Is it 4301? At least available easily enough. http://nz.rs-online.com/web/p/plastic-rods/2577136/Yep, that's the stuff. Like I said, it ain't cheap.

[husaberg]

Using high temp? The temp reached by a piston pin in normal use may already melt the silver and send the plugs on an exploratory expedition through the engine.

Good suggestion, except that the small end bearing needles like to have some firm (hard) surface under their feet.
But then why not go all the way and use ceramic pins? They're even lighter and much, much harder than aluminium, and not affected by temperature at all. But they still wouldn't solve the aux/transfer short circuiting. Aprilia closed their big end pins with conical plugs, but that wouldn't solve the aux/transfer short circuiting either.




Torlon ® is the highest performing melt processable plastic. It has superior resistance to elevated temperatures. It is capable of performing under severe stress conditions at continuous temperatures to 500°F (260°C).

Silver solder melts about 800 deg C, so i am confused?
whoops that Degrees F
OK some of the silver solder alloys are 710 deg c is that not high enough.
What temp does it see?
http://www.silfos.com/htmdocs/product_support/alloy_selection_guide.html

With the solid AL Alloy pin you could use as i suggested, a steel sleeve as the vincent Grey Flash did for the big end bearing to run in?
Actually the MMC rods made for some of the current MX bikes run the bigend direct with no bearing at all and are lighter as well.
Granted they have a proper pressure oil supply but there are coating available for severe use
https://www.highpowermedia.com/blog/2989/metal-matrix-composite-rods
MMC Same stuff that AP pioneered for brake calipers in the 90's.


PS What held in the Aprilia conical big end covers? just a press fit?


To maintain a proper seal is a mater of changing the design of the piston. ie piston manufactuers problem, where is Ken?
closing the ends is all that was originally asked:lol:
I do silly ideas not R&D.

[Hemi Makutu]

www.belonptfe.com/ptfe-products/ptfe-rods/

[wobbly]

Teflon, hell no.
Look at the Tensile numbers 14 MPa Vs 164 for the Torlon.
About as strong as the skin on a rice pudding.

The Aprilia pins had the cover plates laser welded - same process used to attach fine wire earth electrodes on racing plugs.

[jfn2]

I bought a Torlon rod # 4203 last march and I paid $116 plus shipping USD for a 12" long x 1" dia piece. It would have been cheaper for a smaller dia.
I made my plugs for a KTM 250 per Frits' picture and they are working fine. Lets say you use 1/2 " per plug you can make 12 sets and Frits is correct they seem to work ok for at least 2 times. I used the same clearance for the plugs as the piston uses against the cyl wall. They just snap into the circlip groove. I did have to give the plug some clearance for the piston pin hole in the piston. Also I found out that the chamfer that you use at the beginning of the plug is critical without having to chamfer the piston pin hole. Also you should use a rounded design that fits into the circlip groove instead of the pointed one shown on Frits' drawing. Also had to cut 6 slots instead of 4 as in Frits' drawing. I had a very hard time installing with only 4 slots and could not get out. But once you have it right it installs with a very distinct snapping sound. We'll see how long they last.

[Hemi Makutu]

Teflon, hell no.
Look at the Tensile numbers 14 MPa Vs 164 for the Torlon.
About as strong as the skin on a rice pudding.

What if you cut a length of the squashy teflon rod sausage-wise, & filled the pin with it entirely?

The internal pin taper ought to keep it located, perhaps?

[Larry Wiechman]

Trouble is I have tried several variations of "plastic " plugs that use the clip for retention, and discovered that this limits the lubrication of the pin in the piston.
The pin ends up getting locally overheated.

I'm curious why the pin is allowed to rotate in the piston bores. It would seem that is a job for the small end rod bearing.


Are you coming to Vegas next week, Wob?

[wobbly]

Yep, you can pick me up from the airport on Tuesday lunchtime, as long as I make it thru security with a bag full of newly tested reeds, manifolds
and mufflers smelling of hydrocarbons.

[Grumph]

Yep, you can pick me up from the airport on Tuesday lunchtime, as long as I make it thru security with a bag full of newly tested reeds, manifolds
and mufflers smelling of hydrocarbons.

Good luck with that - a mate coming back from The BS at Philip Is a couple of years back got picked out by a sniffer dog who liked avgas....

[Peter1962]

The KZ10B piston skirt does close off completely the boost port exit at TDC, but I have narrowed and shortened a piston skirt
thinking that it would help intake flow at BDC - sorry no free lunch.
At BDC there is no intake flow till the piston timing edge is approaching TPC, and at TDC if the boost port is open, the other end is subjected to the same case depression
so there can be no flow.
Re port linking on this engine.
The stock setup has virtually no linking of the Aux and the A transfer by the pin hole as it passes them. Plugs in this case make NO power at all.
But widen the Aux top edge around to bore center, extending the teardrop shape along with a good angled/radiused back corner, and huge gains in peak and overev power suddenly appear.
This is at the expense of around 2 to 3 Hp at 10,000 - drivers hate this even if the lap times are well faster.
My feeling is that if the transfers were left stock and the main/aux Ex port were lowered with this mod that increases blowdown flow, good gains would be had everywhere.
Plug the pin and you get most of the bottom end back, but this mod has little effect approaching and past peak power.
Trouble is I have tried several variations of "plastic " plugs that use the clip for retention, and discovered that this limits the lubrication of the pin in the piston.
The pin ends up getting locally overheated.It never actually failed on me in use, but I now see the value in why Jan used Pankle at great expense to weld a thin plate
over the pin end on his Aprilia.
Also here is what happens if the plug is too close to the bore - one National title of the last 4 gone up in smoke.


Wobbly, would a similar modification on a KTM 250 be a good move ? Or is the shape of the main exhaust and the auxiliaries of better design than that in the KZ10b ?

[ken seeber]

The plugs of Frits’s design are axisymmetric in the outer end whereas Wob’s were of the full piston side skirt shape, hence requiring indexing and unfortunately, more end clearance and were of a single use design. The Torlon was incredibly expensive, but in our case, the freight from the US was even greater (despite our requests to use another freight company).
From Wob’s pic, they do look overly warm at the ends, this being within the pin boss area, suggesting that both the lubrication and cooling ventilation have been reduced with the plugs. This in itself probably isn’t a problem, as LW rightfully points out that the pin bearing should be able to cope with the bearing function, even if the pin was fixed in the piston. So why do we let it rotate in the piston?
A 4 stroke which has the benefit of a total load reversal at TDC overlap allowing an oil film to be re-established every cycle, is quite happy with a plain bearing giving it good/excellent durability. A 2 stroke doesn’t, so at higher speeds, the load of the piston via the pin is always downwards. Here a needle roller bearing is quite good under these conditions, whereas a plain pin bearing struggles. I know old Villiers etc had plane bush bearings, but these were hardly high revvers.
Ultimately the engine must be assembled and disassembled, and the removable pin, as we know it, allows that. By allowing the pin to rotate within the piston does allow an oil film to be sort of maintained. At Orbital we did have a problem with the 3 cyl DI engine of piston pin poundout of the pin bores in the piston. One thought was that the pin wasn’t rotating, allowing cold welding of the aluminium onto the pin, initiating failure. We cut a hole in the front of the #1 cylinder such that we could see the piston pin when at BDC. We then marked the end of the pin and set up a high speed camera. Sure enough. The pin rotated, albeit slowly, in relation to the rpm of the engine. In that case, we solved the problem by roller burnishing the pin bore after boring and then having the bore hard anodized. Mahle did this in Oz for the compression ring grooves in the Turbo Falcon to prevent cold welding to the sealing face of the rings.
So, if the pin ends in Wob’s case were overheating a bit, but didn’t cause any problems in the interface between the pin and the pin bosses, then it’s probably a non-issue. However, if the higher temp carries across to the needle roller bearing and pin interface, causing softening of the pin (from the usual 62 Rc hardness), then that may be an issue. On that, I would think that anything softer, like an Al alloy, in conjunction with a roller bearing would be doomed to failure.
Carrying this thought process across, maybe that if the pin boss bore was slotted (say like Frits’s and others webbed piston design) then this, perhaps in conjunction with some cross drilling of the pin that might align with the slots as the pin rotates, might allow for improved ventilation and lubrication, despite the blocking off due to the plugs. See shitty sketch.

326145

[Hemi Makutu]

I'd love to discover a material that is closed to gases and open to liquids. Might get me a Nobel price, so I could fly to Stockholm, all expenses paid, and meet Bob Dylan...

Sorry Frits, but NACA already did it about 60 years ago.. the gas stream 'sees' the matrix as a 'semi solid'.


https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930084436.pdf

[41juergen]

That's how I try it. For the caps I used the same material as the piston pin and than got it laser welded from a local company, costs were 35,-€ for 2 piston pins. Hope it will work and last... :msn-wink:

326146326147326148

[Frits Overmars]

That's how I try it. For the caps I used the same material as the piston pin and than got it laser welded from a local company, costs were 35,-€ for 2 piston pins. Hope it will work and last... :msn-wink:
326146326147326148I like that timing edge on the piston :rolleyes:.

[bjorn.clauw.1]

Most of the research went into finding the proper plug material. And since I don't expect I'll ever get rich from selling plugs, I'll let the cat out of the bag:
the plugs are made of Torlon. The stuff ain't cheap, but you'll get about 20 re-usable(!) plugs for the price of one Pankl pin.

326134 326135


Does this mean you can provide these plugs? :rolleyes:

[Flettner]

If someone wanted to provide the material I have a CNC that says it could make a few. A detailed drawing might be nice too.

[wobbly]

Flettner, I have two pieces of Torlon on the way for 16mm pins.
I will be away for a week in Vegas, they should be here about the time I get back.

[Hemi Makutu]

Would the weight penalty preclude trying them in the piston to support the pin?

Or alternatively, blind-end/one piece-capped sintered bronze bushes inserted likewise?

[adegnes]

Put me on the list for 12mm caps!


https://youtu.be/C9X2eOzACmk


https://www.youtube.com/watch?v=C9X2eOzACmk&spfreload=10

Feel I need to make something with high precision from good plans next, to redeem my reputation.

[41juergen]

I like that timing edge on the piston :rolleyes:.

Hey Frits, well spotted (of course you do :yes: ). Will get back the barrels next week, modified to take the CNC machined head following the radius at the edge. Fortunately the stock TZR250 3XV barrels have very low timings, so perfect to get the right timing without using too much epoxy....

[Haufen]

That may not break the pocelain but it can very well cause an different problem. An open ended wrench bears on just two points of the hexagon and as the spark plug body is relatively thin-walled, you'll risk pushing the hexagon out of round, causing leakage at the top seal between the hexagon and the porcelain.



Thanks, I will keep that in mind. Although a quick inspection of the broken plugs revealed that all of them were fine in the transition area between the hexagon and the porcelain.
I will now carefully mount the new plug with the proper tooling and report back when I have new findings.


Hey Frits, well spotted (of course you do :yes: ). Will get back the barrels next week, modified to take the CNC machined head following the radius at the edge. Fortunately the stock TZR250 3XV barrels have very low timings, so perfect to get the right timing without using too much epoxy....

Nice modification, how did you carry it out? And did you already test the mod? Did you have to relocate the barrel due to the longer effective port timings to get the same shape of the power curve as before?

[41juergen]

Ok, after 2 years reading, asking and learning may be I should be brave enough to show what I'm working on. :sweatdrop

The bike is a TZR250R type 3XV which was sold in Japan only. There were 2 different versions available (as the RGV's and the NSR's): the standard road bike and the SP versions (with dry clutch, different gearing and better suspensions). I own the R standard version which had only 45HP based on the Japanese power limitations based on their regulations. That engine has very low port timings (ex port only 184°CA and transfers about 118°CA).
So I took Frits proposal of the radiused timing edge followed by Wob's recommendation of the 7° taper and the flat dome for the piston. The heads got inserts based on that geometry and the 6mm distance from piston to plug tip. I used EngMod to define the transfer port and exduct dimensions, all based on a road going bike setup (the second engine will be the track one). The max power will be around 11.000 rpm, the track engine approx. 12.500 rpm.
As I wanted to stick with the stock pipe (because of the German police :eek5:) I only modified the inlet of the pipe based on the 75% exduct area rule (the other engine will get a serious oval to round transition incl. the better pipe). I also followed Wob's idea how to setup the reeds incl. different strength of the upper and lower carbon membrane plates (as the engine geometry required a downstream design to fit the carbs).Further I modified the cooling circuit with the larger curved rad from the TZ with larger hose / pipe diameters and wait for a higher pump impeller. The engine is not complete yet, so I need to see if the result will be close to the EngMod prediction...

326158326159326160326161326162326163

[adegnes]

Ok, after 2 years reading, asking and learning may be I should be brave enough to show what I'm working on. :sweatdrop

The bike is a TZR250R type 3XV which was sold in Japan only. There were 2 different versions available (as the RGV's and the NSR's): the standard road bike and the SP versions (with dry clutch, different gearing and better suspensions). I own the R standard version which had only 45HP based on the Japanese power limitations based on their regulations. That engine has very low port timings (ex port only 184°CA and transfers about 118°CA).
So I took Frits proposal of the radiused timing edge followed by Wob's recommendation of the 7° taper and the flat dome for the piston. The heads got inserts based on that geometry and the 6mm distance from piston to plug tip. I used EngMod to define the transfer port and exduct dimensions, all based on a road going bike setup (the second engine will be the track one). The max power will be around 11.000 rpm, the track engine approx. 12.500 rpm.
As I wanted to stick with the stock pipe (because of the German police :eek5:) I only modified the inlet of the pipe based on the 75% exduct area rule (the other engine will get a serious oval to round transition incl. the better pipe). I also followed Wob's idea how to setup the reeds incl. different strength of the upper and lower carbon membrane plates (as the engine geometry required a downstream design to fit the carbs).Further I modified the cooling circuit with the larger curved rad from the TZ with larger hose / pipe diameters and wait for a higher pump impeller. The engine is not complete yet, so I need to see if the result will be close to the EngMod prediction...

326158326159326160326161326162326163

Great stuff! Looking forward to seeing how it goes!
Is that the stock reedbox? Did you modify it?(other than changing reeds) Could be usefull in other applications with how it's angled!

[koenich]

Feel I need to make something with high precision from good plans next, to redeem my reputation.

this my truing tool. 2 lasered vertical plates and 2 lasered v's:

326165

was only few bucks to get the stuff lasered and can be upgraded with small bearings + discs to balance cranks.

[adegnes]

this my truing tool. 2 lasered vertical plates and 2 lasered v's:

326165

was only few bucks to get the stuff lasered and can be upgraded with small bearings + discs to balance cranks.

Wows! Sexy!
I think I need to plagiarize that, just do it by hand - You know, the thing about my reputation...

[TZ350]

this my truing tool. 2 lasered vertical plates and 2 lasered v's:
Wows! Sexy!
I think I need to plagiarize that, just do it by hand - You know, the thing about my reputation...

I had a rough hand cut one, they work just as well, but don't look so pretty. I sure like Koenich's laser cut version, very impressed.


Ok, after 2 years reading, asking and learning may be I should be brave enough to show what I'm working on. The bike is a TZR250R type 3XV which was sold in Japan only.

I love it, please post more and pictures too as the project progresses.

[F5 Dave]

We got quite a lot of 3XVs here nice looking bike. At least one is a local bucket. Used to be quite cheap a few years back, a couple of mates had SP's Not so much now. TZ racers would use the cases as backup engine bassis.

[TZ350]

326168

Talked with a very interesting guy the other day who was very knowledgeable and helpful. Richard has a business supplying specialty items for the classic two stroke racers and road bikes, a great range of very useful stuff can be found on his site.

https://www.accu-products.com/

326167

After seeing how easily a Honda RS125 rider started his bike on our dyno with one of Richard's starter tools. Team ESE just had to invest in a couple of them and a bunch of spare starter nuts for their race bikes, we can't wait to get them, they should be here in a few days.

I had not seen them before but these starter tools are so easy to use I just had to tell you about them.

Lots of other useful things on the Accu-Products site, well worth poking around to see what would be helpful for your own race bike.

[Frits Overmars]

this my truing tool. 2 lasered vertical plates and 2 lasered v's. was only few bucks to get the stuff lasered and can be upgraded with small bearings + discs to balance cranks.That's right. The friction of a crankshaft in a couple of V-block is far too high for good balancing. But add a couple of discs and you're in business.
326169 326170

[wobbly]

Last time I was in Italy at the Pavesi factory i bought these off them.
The use of large diameter wheels makes the bearing friction torque virtually nothing.
Great idea to copy for Adegnes.

[adegnes]

Maybe discs from an old hard-drive could be used.
I'll look into it in the future.
https://youtu.be/apTo-yho0YI

[Frits Overmars]

I'll look into it in the future.When will you be back?
326185

[adegnes]

When will you be back?
326185

I'm back and I'll tell you it's not pretty, man! Don't go there!

[ief]

Everything electric? ;)

[peewee]

well im still trying to get this ktm head sorted out. made the first cut and the squish band angle was way off. thought the piston dome was 17* but i was wrong. made another cut about 15.5* and its still to steep so ill try to figure it out on paper before anymore cuts. i wont be able to cut the radius in the head band to match the piston but should i try to get close to a paralell / slightly diverging toward bore center squish gap ?

[lodgernz]

i wont be able to cut the radius in the head band to match the piston but should i try to get close to a paralell / slightly diverging toward bore center squish gap ?

You probably can match the squish to the piston dome.
It sounds like you have a lathe, and it probably has a swiveling toolpost, locked in place by grubscrews or a handle. Once you identify the exact radius of the piston dome, you can set the tip of the tool to be slightly less than that radius from the centre of the toolpost swivel. I say slightly less, because you want to avoid a negative squish angle (=deto), so the squish band radius needs to be a little tighter to produce a positive (diverging) or neutral squish angle.
Then with the grubscrews or handle loosened, you just swivel the toolpost assembly back and forth by hand, taking tiny cuts (since it won't be mechanically controlled). Works a treat.

Hardest part is identifying the exact centre of the toolpost pivot. Piston dome radius can also be tough to determine as some aren't a pure spherical cap.

Obviously this technique won't be feasible if the dome radius is more than about 100mm.

[emess]

Once you identify the exact radius of the piston dome

To find the radius of the piston crown I believe this will work - assuming it is part of a sphere,

1) make a tube with accurately known height and inside diameter.
2) place it on the piston and measure the height of piston protruding into the tube (see image)

using h for the protruding height and d for the inside diameter of the tube the piston crown radius can be found from

(h^2 +d^2) / 2h


Mick

326202

[Pursang]

Last page, finally got here after months (only 1605 pages and 24000 posts read):wings:
My complements to All the contributors, over the 8 years, SO MUCH great information.

Here is a pic from an old patent that seems to contain some relevant elements of a Ryger style engine.
https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/US4724800-1+Ringless+2T.png

A bit more Bleed down STA is required.
The internal piston cooling might need to go, definitely rev limiting and not KISSable.
And it should have a 24/7 flap valve in the inlet to the transfer chamber.

Cheers, Daryl.

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[lodgernz]

To find the radius of the piston crown I believe this will work - assuming it is part of a sphere,

1) make a tube with accurately known height and inside diameter.
2) place it on the piston and measure the height of piston protruding into the tube (see image)

using h for the protruding height and d for the inside diameter of the tube the piston crown radius can be found from

(h^2 +d^2) / 2h


Mick

326202

A cylinder like the one the piston sits in, is a good tube to use.
The formula I've been using is :

(4*(h^2) + (d^2)) / (8*h)

Yours is a lot simpler and gives very different results. Are you sure it's correct?

[emess]

A cylinder like the one the piston sits in, is a good tube to use.
The formula I've been using is :

(4*(h^2) + (d^2)) / (8*h)

Yours is a lot simpler and gives very different results. Are you sure it's correct?

I believe your formula is exactly the same except the top and bottom of your formula are both multiplied by 4. Dividing both the top and bottom by 4 gives 2h on the bottom so both formulae should give the same answer.

[EssexNick]

My first post here, so I would like to thank everyone on this thread. I've been blown away by the generosity and cooperation of you guys. This is the best thing I've read in years.

[tjbw]

Last page, finally got here after months (only 1605 pages and 24000 posts read):wings:
My complements to All the contributors, over the 8 years, SO MUCH great information.

Here is a pic from an old patent that seems to contain some relevant elements of a Ryger style engine.

...

A bit more Bleed down STA is required.
The internal piston cooling might need to go, definitely rev limiting and not KISSable.
And it should have a 24/7 flap valve in the inlet to the transfer chamber.



Congratulations Daryl, and thanks for that interesting patent find.

Imagine a Ryger without piston ring friction etc, must be worth at least 80HP ;)

[Frits Overmars]

Last page, finally got here after months (only 1605 pages and 24000 posts read):wings: My complements to All the contributors, over the 8 years, SO MUCH great information.Thanks Daryl. Now, if you've regained your breath, here's some more reading. It's only 302 more pages, a piece of cake for someone with your perseverance.

http://www.kiwibiker.co.nz/forums/showthread.php/171300-Oddball-engines-and-prototypes/page70

http://www.kiwibiker.co.nz/forums/showthread.php/162399-The-Bucket-Foundry/page177

http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis/page55


Here is a pic from an old patent that seems to contain some relevant elements of a Ryger style engine.Don't go there. I would not want you to hurt your brain after all those nice words that you just wrote.
From your nickname, may I take it that this logo is not completely alien to you?
326215


My first post here, so I would like to thank everyone on this thread. I've been blown away by the generosity and cooperation of you guys. This is the best thing I've read in years.Thanks Nick. We'll drink to that :drinknsin.

[Pursang]

Imagine a Ryger without piston ring friction etc, must be worth at least 80HP ;)

and 30,000 rpm potential.

Ring-less piston solves a number of problems and satisfies Harry Ryger's own statement.

Piston cooling & heat transfer by a fresh air/fuel charge in the gap each revolution.
Even cooling and lack of mechanical contact keep bore & piston round so the gap can be very narrow.

Protected from the combustion by the squish band and the narrowness of the gap itself.
The trapped squish gas (cooler) is first to go back down the gap.
Combustion pressure front chases the descending piston so leakage down the gap is relatively small.

Any Pressure loss is returned to the transfer chamber, for use next cycle.

2 sealing rings are fitted, at the top & bottom of the cross head linear bearing.

Cheers, Daryl.

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Pursang]

Don't go there. I would not want you to hurt your brain after all those nice words that you just wrote.
From your nickname, may I take it that this logo is not completely alien to you?
326215

Thanks Frits, but it's too late too protect this poor brain.

Yes, love my Bully's. They defy just about every element of modern, acceptable 2T practice, (except, perhaps, some bits of expansion chamber design) but despite all that produced great results in their time.

I'll get stuck into the other threads soon.

Cheers, Daryl.

[Flettner]

My first post here, so I would like to thank everyone on this thread. I've been blown away by the generosity and cooperation of you guys. This is the best thing I've read in years.

Nice, 73 Kawasaki, good year!

[lodgernz]

I believe your formula is exactly the same except the top and bottom of your formula are both multiplied by 4. Dividing both the top and bottom by 4 gives 2h on the bottom so both formulae should give the same answer.

Your maths is a bit rusty I fear.

My formula can be simplified to:

(d^2)/8h + h/2

Not the same as yours at all.

Run some numbers through both formulae and compare the results.
For my bike's head, the dome radius is 77mm with my formula, 2063mm with yours. Bit of a difference.

[EssexNick]

Nice, 73 Kawasaki, good year!

Thanks, but this one is a total heap. It is, however, the reason I found my way here. I'm looking at the motor with a few ideas and this is the place to be.

[adegnes]

Last page, finally got here after months (only 1605 pages and 24000 posts read):wings:
My complements to All the contributors, over the 8 years, SO MUCH great information.


My first post here, so I would like to thank everyone on this thread. I've been blown away by the generosity and cooperation of you guys. This is the best thing I've read in years.

+1

New series!
Clickbait? What? Who, me?

https://www.youtube.com/watch?v=cXyGJ8f8F78


https://www.youtube.com/watch?v=cXyGJ8f8F78

[emess]

Your maths is a bit rusty I fear.

My formula can be simplified to:

(d^2)/8h + h/2

Not the same as yours at all.

Run some numbers through both formulae and compare the results.
For my bike's head, the dome radius is 77mm with my formula, 2063mm with yours. Bit of a difference.

You are absolutely right lodgernz. I can only claim bracket dyslexia for mangling your formula and crap memory for getting my original post wrong.

On checking carefully (like I should have before) I see the formula should read (h^2 + r^2) / 2h

where r is the radius of the tube not the diameter.

This one does give exactly the same result as your formula and has been used successfully to make several heads.

[Hemi Makutu]

well im still trying to get this ktm head sorted out. made the first cut and the squish band angle was way off. thought the piston dome was 17* but i was wrong. made another cut about 15.5* and its still to steep so ill try to figure it out on paper before anymore cuts. i wont be able to cut the radius in the head band to match the piston but should i try to get close to a paralell / slightly diverging toward bore center squish gap ?

Hey P-W, Check out what Dick does with them..

http://www.dicksracing.com/motorcycle_performance#2stroke

[Flettner]

Hey P-W, Check out what Dick does with them..

http://www.dicksracing.com/motorcycle_performance#2stroke

WOW, 'power channels' in the head. :laugh:

[Hemi Makutu]

'Singh grooves' maybe?

http://www.richstaylordporting.com/image/photo_TorqueGroves_Head_2.jpg

Or, like here: www.datafan.com/twostroketuningbimotion/twostroketuningbimotion.php

Bet you know what this one is, eh Flettner...

http://www.klemmvintage.com/deto%20pix%20004.jpg

See: http://www.klemmvintage.com

Have to comment, Klemm seem a bit too self-satisfied about getting 180 Km/h from a Kawasaki H1 triple..
..when the original `69 models did 200 Km/h showroom stock, & won their class at the Bol d' Or 24 Hour...

[Pursang]

'Singh grooves' maybe?

http://www.richstaylordporting.com/image/photo_TorqueGroves_Head_2.jpg

Had a good discussion on those years ago in the 'Banger' thread on the HAMB. (Bangers are 4cyl Flatheads).

Flatheads have shocking shaped chambers and some directional control of gas from the squish might be helpful.
(in high performance ones the squish can be 90% of the piston area).

My thought is that the grooves allow the flame front(s) to access the squished gasses and allow them to be burnt as part of the combustion process.
i.e. The combustion pressure forces the flame deep into the squish via the groove channels. The descending piston allows room for the combustion.

If it actually works, it's a good thing. :niceone:

Don't want them in a Ringless engine.

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Hemi Makutu]

Yeah, some of these 'groove' ideas have been around for a while...

Decades ago, when I was into original Triumphs, amongst the 'porting lore' was a high comp piston 'trick'..

The deep hemispherical dome of the Triumph head made room for big valves, but then needed a real lumpy piston
to fill it up for a decently high comp ratio.. which tended to block flame travel from the spark plug.. ( the big valves
didn't leave room for a centrally mounted plug).. & twin plug head conversions were costly..

The Triumph 'tuner' approach was to cut a 'flame groove' across the edge of the piston crown from the ( indexed)
plug to the top of the combustion chamber, & yeah, it too was reputed to be worth the ( minimal) effort of doing...

[TZ350]

'Singh grooves' maybe?

http://www.richstaylordporting.com/image/photo_TorqueGroves_Head_2.jpg

Or, like here: www.datafan.com/twostroketuningbimotion/twostroketuningbimotion.php (http://www.datafan.com/twostroketuningbimotion/twostroketuningbimotion.php)

I can see the possible sense in using a flame grove in a 4T but the talk is not positive about them for a 2T. But if anyone wants to front with a bike fitted with one of these heads and an identical head without the groves I would be happy to run a back to back dyno test on them for free so long as the results and pictures can be posted on here.

[TZ350]

326255

Thanks to help from a few friends, Gigglebutton, Kel and Chambers the Team ESE dyno finally has an exhaust extractor.

326254

The last few days we have been working on improving the power spread on an air cooled 2T for the 2-hour.

326253326256

Had a few problems, cracked piston, now that is not supposed to happen with forged pistons and a rotated ring that got court in the exhaust port. This is the third Wiseco piston that has done this to me. The ring peg gets pushed or works back in its hole and then the ring rotates.

[Flettner]

326253326256

Had a few problems, cracked piston, now that is not supposed to happen with forged pistons and a rotated ring that got court in the exhaust port. This is the third Wiseco piston that has done this to me. The ring peg gets pushed or works back in its hole and then the ring rotates.

Shit wiseco.

[adegnes]

My thought is that the grooves allow the flame front(s) to access the squished gasses and allow them to be burnt as part of the combustion process.
i.e. The combustion pressure forces the flame deep into the squish via the groove channels. The descending piston allows room for the combustion.

If it actually works, it's a good thing. :niceone:

Don't want them in a Ringless engine.


But the flame must be reaching the unburnt mixture in the squishband as it is opening up while the piston is descending from tdc with a conventional chamber too. Or? Just seems logic(yeah, I know logic doesn't apply to two strokes...}


I can see the possible sense in using a flame grove in a 4T but the talk is not positive about them for a 2T. But if anyone wants to front with a bike fitted with one of these heads and an identical head without the groves I would be happy to run a back to back dyno test on them for free so long as the results and pictures can be posted on here.

Great idea!

[Pursang]

But the flame must be reaching the unburnt mixture in the squishband as it is opening up while the piston is descending from tdc with a conventional chamber too. Or? Just seems logic(yeah, I know logic doesn't apply to two strokes...}

Squish band mixture is cooler and less dense as the gap opens. May burn slowly, and only from the leading edge, if at all.
Hence the need for a tight squish so as to reduce the waste of this part of the charge.

Hot dense columns of actual combustion, pushed into this 'dead zone', might heat and stir it up enough to be part of the main combustion burn.

I don't know....that's why it's just a speculative thought and not a theory. :apint::

I'm not working (for money) at the moment, I'll happily accept a generous grant to run some conclusive tests.
( May involve a trip to NZ & a play with Team ESE's Dyno.)

By the way TZ, the extraction pipe looks great, but a bit too four stroke, needs a bulge in the middle.

Cheers, Daryl.

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[adegnes]

.

I don't know....that's why it's just a speculative thought and not a theory. :apint::



Me neither...
Welcome to the forum!

[Grumph]

Singh slots have been discussed before on here. I asked the question at the time "would you want a stream of oily unburned mixture squirted at the plug?" It went a bit quiet after that....
There is of course the possibilty of arranging them at an angle so as to promote rotation of the mixture - but I have no idea how that would impinge on the existing squish regime. On balance probably badly IMO.

[41juergen]

Great stuff! Looking forward to seeing how it goes!
Is that the stock reedbox? Did you modify it?(other than changing reeds) Could be usefull in other applications with how it's angled!

Thank's Alex, up to now I only cleaned up the reed case rubber ridge were the reeds contact the case. I will start with Wob's recommendation how to set up reeds (with spacer and the stopper plates). Also I got reeds with 2 different stiffnesses, the upper one (named "oben" on the picture) will get the stiffer one, the lower reed will have a slightly lower stiffness.

326257 326258

[husaberg]

Also I got reeds with 2 different stiffnesses, the upper one (named "oben" on the picture) will get the stiffer one, the lower reed will have a slightly lower stiffness.


If you are going to name your reeds, may i suggest Frits and Wayne?

[F5 Dave]

Dyno extractor.

We dearly need one of those and ideally a clean air feed to the fan. Not likely to happen, but this dyno used to live in such an environment along with soundproof room. It was awesome.

Now the starter motor is f`d and its in a glorified shed, albeit with an industrial fan.

Didn't help much running methanol. Eyes started watering. Just couldn't stay in there. Poisonous stuff I'm sure.

Usually come home and jump into bed next to the wife ponging of 2 stroke smoke.

Not sure why she smells like that. I guess it could be me.

[Hemi Makutu]

Dyno extractor.

We dearly need one of those and ideally a clean air feed to the fan. Not likely to happen, but this dyno used to live in such an environment along with soundproof room. It was awesome.

Now the starter motor is f`d and its in a glorified shed, albeit with an industrial fan.

Didn't help much running methanol. Eyes started watering. Just couldn't stay in there. Poisonous stuff I'm sure.

Usually come home and jump into bed next to the wife ponging of 2 stroke smoke.

Not sure why she smells like that. I guess it could be me.


Could be worse.. a 4T flogged real hard on the dyno will more likely give off an oil smell like death, too..


( & @ huhubug.. FYI - Frits is a disc valve fancier, surely..)

[41juergen]

If you are going to name your reeds, may i suggest Frits and Wayne?

That's a good idea! May be that will give the engine even a bit more power? :sunny:

[Hemi Makutu]

Singh slots have been discussed before on here. I asked the question at the time "would you want a stream of oily unburned mixture squirted at the plug?" It went a bit quiet after that....
There is of course the possibilty of arranging them at an angle so as to promote rotation of the mixture - but I have no idea how that would impinge on the existing squish regime. On balance probably badly IMO.

What would you have ignite a nice oily mixture ( & an oily 16-to-20:1 gives best power, no?),

HCCI?

[rgvbaz]

326255

Thanks to help from a few friends, Gigglebutton, Kel and Chambers the Team ESE dyno finally has an exhaust extractor.

326254



TeeZee,

What fan are you using for extraction?

We need to get one for our dyno.

Cheers

Dave

[adegnes]

TeeZee,

What fan are you using for extraction?

We need to get one for our dyno.

Cheers

Dave

I'm using a gutted propane heater, works ok(for 50cc atleast).
http://www.masterheaters.com/Desa_images/blp375t.jpg

I've actually got a proper exhaust extraction fan, but that's used for cooling. When I think about it my bike always seems to be "overcooled" on the dyno, might switch them around.

http://img.directindustry.com/images_di/photo-g/13788-8404734.jpg

[Frits Overmars]

Shit wiseco.I was pondering about a polite way to express my opinion but you made it a lot easier for me Neil. All I need to add is '+ 1'.


If you are going to name your reeds, may i suggest Frits and Wayne?
Frits is a disc valve fancier, surely.Used to be, Hemi, used to be. Now it's 24/7 all the time :yes:.


By the way TZ, the extraction pipe looks great, but a bit too four stroke, needs a bulge in the middle.Like these after-dinner pythons? (they even look hydroformed) 326260 326261 326262

[Frits Overmars]

Had a few problems, cracked piston... This is the third Wiseco piston that has done this to me.
326264
"We cannot advise strongly enough against unbridled spinach consumption prior to handling our delicate products".
popeye@wiseco.com

[speedpro]

My old RG400 pistons in my TS100 used to come out looking like that after 2 meetings. It never broke but only because I replaced them regularly, every 2 meetings. I used to prep them by radiusing the edge of the bottom of the piston and polishing it as well. didn't seem to help but made me feel better.

[Peter1962]

I was pondering about a polite way to express my opinion but you made it a lot easier for me Neil. All I need to add is '+ 1'.

Used to be, Hemi, used to be. Now it's 24/7 all the time :yes:.



Is your experiment with Roland Holzner-Modena that conclusive ? I know we are speaking on an abstract level since the actual race rules exclude alle 2 stroke development, but if it were permited, would you choose a 24/7 over a rear rotary valve like on the RSA if you were asked by a constructor to make them a winning 125cc mono at world championship level ?

[EssexNick]

Cutting grooves across a squish band just seems wrong to me. Wouldn't that undermine the reason and benefits behind the squish band and just promote chronic hot spots? Or am I missing something here?

[190mech]

If cutting grooves in the squish helped,why didnt the TopGun tuners use it?I'm sure Mr. Jan Thiel tried it or disqualified it do to 2T physics..

[Pursang]

326253326256

Had a few problems, cracked piston, now that is not supposed to happen with forged pistons and a rotated ring that got court in the exhaust port. This is the third Wiseco piston that has done this to me. The ring peg gets pushed or works back in its hole and then the ring rotates.


Here is a solution to that problem.https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Ringless+Piston+trial.pdf

Don't need to worry about cross heads and linear piston movement.

Just make your own Ringless, Chrome plated, Steel pistons. Keep the revs over 5000. :2thumbsup

Cheers, Daryl.


"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Pursang]

This is from the patent shown earlier:

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/US4724800-2+Ringless+2T.png

From 6000 up, with a 0.001" gap, the ringless engine BHP exceeds the ringed one. Fig4 (apparently)

Independent dyno testing for verification is required.

Cheers, Daryl.


"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Pursang]

Used to be, Hemi, used to be. Now it's 24/7 all the time :yes:.


So that's 24/7 X 24/7 = 11.755 :wavey:

[TZ350]

326268


TeeZee, What fan are you using for extraction? We need to get one for our dyno. Cheers Dave

Cant see it in the picture but the exhaust fan has been put inside a piece of air duct that used to go around a pot belly stove chimney. The fan itself is a 200mm 400V 3 phase unit a friend rescued from the skip for me so I don't really know where you could buy one. Behind Cully is another 200mm fan that draws fresh air from outside and blows it over the dyno operators.

For an exhaust extractor fan, the gutted propane heater looks a very good idea.


I'm using a gutted propane heater, works ok(for 50cc atleast).

http://www.masterheaters.com/Desa_images/blp375t.jpg

[Hemi Makutu]

Used to be, Hemi, used to be. Now it's 24/7 all the time :yes:.


An academic paper researching 'knock sensor' applications to small 2T mills ( Husqvarna chainsaw) - if of interest.

http://liu.diva-portal.org/smash/get/diva2:698453/FULLTEXT01.pdf

[TZ350]

Here is a solution. https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Ringless+Piston+trial.pdf

Don't need to worry about cross heads and linear piston movement. Just make your own Ringless, Chrome plated, Steel pistons. Keep the revs over 5000. :2thumbsup Cheers, Daryl.

My engine idles at 3,500 rpm and makes power from 7,500 up and max's out at 12,500.

Thanks Daryl. it's very interesting, I see the experiment was done by the USAAC ... US Aviation Army Command using a water cooled Suzuki RM250 engine, so done by a reputable institution on a practical real world engine.

Now to read it all carefully to see how it went and what gems there are if any.

[Hemi Makutu]

www.google.ca/patents/US8127544

HCCI opposed piston..

[Hemi Makutu]

Those 'Singh grooves' seem a tad basic..

Now if some talented machinist was game to try cutting a Fibonacci...

http://realneo.us/system/files/Slide2_76.JPG


...or Schauberger, dynamic flow pattern..


http://i.ytimg.com/vi/8M81_FRbTLc/hqdefault.jpg

[TZ350]

Here is a solution. https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Ringless+Piston+trial.pdf

Don't need to worry about cross heads and linear piston movement. Just make your own Ringless, Chrome plated, Steel pistons. Keep the revs over 5000. :2thumbsup Cheers, Daryl.
My engine idles at 3,500 rpm and makes power from 7,500 up and max's out at 12,500.

Thanks Daryl. it's very interesting, I see the experiment was done by the USAAC ... US Aviation Army Command in part using a water cooled Suzuki RM250 engine, so done by a reputable institution on a practical real world engine.

Now to read it all carefully to see how it went and what gems there are if any.

Ok, I read the whole thing. They had more seizures than I could live with. It was mostly about comparing the performance of a alloy and a steel ringless piston and neither made more or anywhere near as much power as the RM's conventional ringed alloy piston.

The possibilities of getting extra power buy using a ringless piston.

326269

[Pursang]

Ok, read the whole thing. They had more seizures than I could live with. ("This is the third Wiseco piston that has done this to me")

It was mostly about comparing the performance of a alloy and a steel ringless piston and neither made more or anywhere near as much power a conventional ringed alloy piston.

True, but it worked and their process was Very Very Basic.
The alloy piston was a standard one without the rings fitted;
The steel one was a sheet metal, fabricated flat top;
They didn't get results for the ringless engine over 6000 rpm.
Changes to mixtures & jetting were random, if done at all.
Tuning to maintain a constant exhaust gas temp might have created a datum.

Seizures of the chrome steel piston produced no damage to piston or bore and were sanded/polished out.
(Except when the soldered support fell out)
More work was needed to establish gudgeon axis clearance and internal support & thermal control.
Using different materials for piston & liner with greater expansion of liner (Ti & Steel or Steel & Al) could limit seizure with increased temps. Lots to explore here.

Importantly the Patent was registered by the same bloke who did that testing.
Perhaps he saw more in it than the test results that were presented to the army.:whistle:

Cheers, Daryl.

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[jonny quest]

Were combustion pressure and hot gasses burging off the lubrication on piston skirt?

That test definitely wasn't thought out very well. Pretty much a farce

[Pursang]

Were combustion pressure and hot gasses burging off the lubrication on piston skirt?

That test definitely wasn't thought out very well. Pretty much a farce

The pictures were hard to see, but more combustion marks on upper of Al than steel piston.
BUT, so many variables, Gaps, tapers, Cam, operating temps, etc.

The Military Industrial Complex provides grant money to conduct "interesting" experiments on 2T motorcycle engines.....
....and you call that a farce? Shame on you:nono: I want to know where to send the application.:shifty:

"Busted" I don't really know that. Just cos it didn't work great this time, doesn't mean it can't eventually.
Like many of the MythBuster's experiments the result could be quite different with improved set-up & techniques.
(But possibly less Telegenic & less Blow ups)

Look at it this way...they tried some stuff and found out some things that worked better than others.
And they reported what they did and what they found.
Certainly pointing one possible way to low friction, hi reving, more powerful 2T racing engines.

If anybody was looking in that direction (forward?)

Cheers, Daryl


"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Hemi Makutu]

To be fair, Rotax have incorporated composite Fe/Al pistons/Fe bore coat in their hard running E-TEC Ski-Doo mills..

This is to support the ring lands while running on the edge of lean/low lube due to economy/emissions control needs..

[TZ350]

Were combustion pressure and hot gasses burning off the lubrication on the piston skirt?

Certainly one of the possibility's advanced in the study.


"Busted" I don't really know that. Just cos it didn't work great this time, doesn't mean it can't eventually.

Look at it this way...they tried some stuff and found out some things that worked better than others. And they reported what they did and what they found. Certainly pointing one possible way to low friction, hi revving, more powerful 2T racing engines.

If anybody was looking in that direction (forward?)

Yes, like you say I have had enough failed pistons of my own .... :laugh:

These guys were paid to explore the ringless piston idea and publish their findings. Busted, well maybe or maybe not but they certainly put some effort into exploring the basic idea and arrived at a point where my interest in exploring ringless pistons for myself is certainly busted.

The idea was good, certainly cought my interest but I noted that even on the best runs the ringless piston did not make anywhere near the power of a conventional RM piston and ring and the setup was very fragile. They suggested improvements like a labyrinth seal instead of a ring but I suspect that after a lot of effort even the best ringless power wise will only come close to a conventional piston and ring.

I don't imagine I could do better than they did, so thanks to their efforts I now think it would not be worthwhile exploring ringless pistons myself but if anyone has the energy to make the effort, I am happy to do the dyno work for free.

Ringless Pistons ....... I am still struggling with my EFI 2T project.

[Hemi Makutu]

For a defunct technology (Wankel rotary piston engine) a fiddler has obtained nearly a US $ mil to play with..

http://www.businesswire.com/news/home/20150423005821/en/LiquidPiston-Signs-1M-Agreement-DARPA-Develop-Fuel-Efficient

Stupidity/lack of due diligence/kickbacks? Suspicious, sure, but whatever.. Trump might buy it..

Frankly, anyhow you cut it though , such a mill - fundamentally - cannot be 'eco'-trained..

Look at all the really big bucks companies who tried & failed, even Toyo Kogyo 'Mazda' had to flag it, 'ross of face' or no...

[Pursang]

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/liquid.JPG

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/liquid+2.JPG

My Mind is Open...my wallet is closed.

Cheers, Daryl

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Hemi Makutu]

My Mind is Open...my wallet is closed.

Cheers, Daryl

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.


More than that useless lump of flim-flam... but only by 'an order of magnitude' - or so...

[Pursang]

No Apex Seals = No Piston Rings

<iframe src="https://player.vimeo.com/video/64911927" width="640" height="360" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
<p><a href="https://vimeo.com/64911927">LiquidPiston X Engine</a> from <a href="https://vimeo.com/liquidpiston">LiquidPiston</a> on <a href="https://vimeo.com">Vimeo</a>.</p>

[Hemi Makutu]

Unless they can get away with running it so lean/low powered - it makes no pressure/power/heat..

The fundamental epicycloid rotary piston issues with massive combustion chamber area/heat rejection are still there..

[Frits Overmars]

Used to be, Hemi, used to be. Now it's 24/7 all the time :yes:.
So that's 24/7 x 24/7 = 11.755 :wavey:I was wondering if anyone would notice the pun. Glad you did :D.


Look at it this way...they tried some stuff and found out some things that worked better than others. And they reported what they did and what they found. Certainly pointing one possible way to low friction, hi reving, more powerful 2T racing engines. If anybody was looking in that direction (forward?)How about looking back for a change? Then they might have found the rather more thorough research into ringless pistons carried out by the then-leading two-stroke company MZ around 1960. Their conclusion: it won't work.


That test definitely wasn't thought out very well. Pretty much a farce.I'd say that's a pretty good summary Jonny. Among the various phrases that hurt my eye, this took the cake:
"The piston weight must match the stock aluminium piston weight to maintain the proper engine balance"This has nothing to do with thermodynamics or gas dynamics; it's just plain simple mechanical engineering, or rather the lack of it.
Anyone with a basic understanding of reciprocating engines should know that lightening a piston in an engine without balance shaft, such as the Suzuki RM250 that was used for the test, will always reduce the inertia forces and improve the balance (unless you lighten the piston so much that the crank bobweights shift the balance factor to over 100%, which will be practically impossible to achieve).


No Apex Seals = No Piston Rings.The LiquidPiston engine does use apex seals, Daryl. But they're not in the rotor tips, but stationary, in the housing, where they can be better cooled.
I had a discussion with the inventor a couple of years ago. The combustion takes place in a hemispheric chamber which is a huge improvement compared to a Wankel.
But then the exhaust gases are lead down through the rotor, heating it up asymmetrically, which spoils the idea for me.

[Pursang]

I was wondering if anyone would notice the pun. Glad you did (well, actually it's 11,755102 :p). I do Engineering not Science. :bleh:

How about looking back for a change? Then they might have found the rather more thorough research into ringless pistons carried out by the then-leading two-stroke company MZ around 1960. Their conclusion: it won't work.

Maybe, but what if MZ had decided to solve the issues and make it work, they might still be the leading two-stroke company.

There were a lot of things in 1960 that were impossible/implausible/impractical that we now benefit (or suffer) from everyday.

How many back then would have thought that a 125cc single could produce 50+ HP or a two-stroke engine could run effectively with the crankcase exposed to the intake 24/7? :gob:

Cheers, Daryl


"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[lohring]

Here is a solution to that problem.https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Ringless+Piston+trial.pdf

Don't need to worry about cross heads and linear piston movement.

Just make your own Ringless, Chrome plated, Steel pistons. Keep the revs over 5000. :2thumbsup

Cheers, Daryl
[/I][/SIZE]

Ringless pistons have been around in small engines for a long time. They are superior to ringed pistons due to lower friction. They require a special fit and have the advantage that the methanol based fuels run at a lower temperature than gasoline. Very small engines (up to 1.5 cc) have been mass produced with steel pistons in steel cylinders (https://en.wikipedia.org/wiki/Cox_model_engine). The most successful use high silicon aluminum pistons in chrome plated brass liners. This is called an ABC piston and liner (http://gallery.intlwaters.com/thumbnails.php?album=577). Chromed aluminum liners also work and that's called an AAC piston and liner. Those all work well up to around 15 cc. One manufacturer tried his AAC system on a 35 cc gasoline engine. That was a disaster and he went back to a ringed piston.

Lohring Miller

[TZ350]

Maybe, but what if MZ had decided to solve the issues and make it work.

How many back then would have thought that a 125cc single could produce 50+ HP or a two-stroke engine could run effectively with the crankcase exposed to the intake 24/7? :gob:

Cheers, Daryl

I am not sure if it was MZ but it was about that time, someone's disk valve 2T seized the disk in the open position during a dyno run. It was noted that it continued to make full power until the throttle was closed and the revs dropped so 24/7 has been known about for a long time. 24/7 has also been used in old 2T stationary engines where the engine is cranked up to speed and then inlet pipe resonance takes over and keeps it at a steady industrial like tickover suitable for generators, milking machines and pumps.

There are some things that are better acknowledged as being impossible. After a bit of a try most realize that you can't lift yourself up buy your shoe laces. But an enthusiast could buy better shoe laces and keep trying I suppose.

[Frits Overmars]

I am not sure if it was MZ but it was about that time, someone's disk valve 2T seized the disk in the open position during a dyno run. It was noted that it continued to make full power until the throttle was closed and the revs dropped so 24/7 has been known about for a long time.It happened to me in 1973.

[husaberg]

I am not sure if it was MZ but it was about that time, someone's disk valve 2T seized the disk in the open position during a dyno run. It was noted that it continued to make full power until the throttle was closed and the revs dropped so 24/7 has been known about for a long time. 24/7 has also been used in old 2T stationary engines where the engine is cranked up to speed and then inlet pipe resonance takes over and keeps it at a steady industrial like tickover suitable for generators, milking machines and pumps.

There are some things that are better acknowledged as being impossible. After a bit of a try most realize that you can't lift yourself up buy your shoe laces. But an enthusiast could buy better shoe laces and keep trying I suppose.

It was MZ Rob, re the rigless pistons whoops i just noticed you were talking about the valve

but to be fair they had very little metalurgical expertise and were also not able to build decent forks or ignitions or spark plugs.
Pretty sure its mentioned in here, anyway i have posted about it previously.


Kaaden unsuccessfully tried ringless pistons. But his access to metallurgy was known to be poorer than the Japanese or Europeans. yet the Japanese and Euros never went this route either.
Your post there got me thinking about how one some of the tiny aero engines have no rings Secondly if anyone had ever tried a piston design with a Lab type combustion seal arranged of multiple grooved pockets.
Maybe with a better guided piston ring friction and the breaking of seal with tilting is not an issue and design can be different
I do however thing the limiting factor of high speeds breathing limitations was due to blowdown rather than total port area of the EX port. So it might be moot.

Cross heads change the angle to solely up and down they rid the thrust friction due to rod angularity.
That's why modern ringless Compressors use them as they can't allow the gas and the oil to mix otherwise they might explode.
.


Ringless pistons. Of course rings add friction, but the trade-off is that they also provide the proportional sealing of pressures, up to around 90 bar (1300 - 1400 psi) at all sorts of rubbing speeds and high temperatures, not a trivial task. Should they fail, as we’ve all seen with a stuck ring; blowby, loss of lubrication and death.
In a small engine, say a glow plug, one seemingly can get away with it, mainly due to viscous sealing because of the typically 20% oil quantity in methanol &/or nitro fuels, and possibly lower overall temperatures inherent in small engines due to the surface area to volume ratio effect providing a much greater heat transfer rate, at the expense of inherent lower overall thermal efficiencies.
Another thing that has been demonstrated, is that the crevice volume, formed between the bore and the top land above the ring, can result in trapped mixture, leading to unburnt HC emissions. This is why rings have been become higher up the piston. This is not so critical in a stratified charge running condition where, hopefully, only air or burnt gases enter and leave the crevice volume.
I am personally of the belief that a large percentage of the heat from the piston is transferred via the ring and rubbing contact of the ring land (the hottest part of the piston) against the bore. This effect is greatest at the TDC and BDC, where the piston land and ring area have the greatest residency time over the cycle. It is for this reason that cooling of the cylinder is best directed at the very top and also adjacent to the BDC area, usually within the transfer passage cup handles.
.
I think its interesting but a dead end, there is more pressing problems limiting a two stroke emissions etc.
interstingly reading about the Vdue Bimota it seems most of the problems it intitially had have been solved and traced to poor fuel mapping and leaky crankcases casting poor seal design and poor assembly detail.

Ed. Note December 2013 - Since writing this piece in 2012 I've learned that the main problem with the V-Due is improper crankcase sealing due to flaws in the crankcase castings, not simply a wonky fuel injection setup. You can fix a V-Due! Bob Steinbugler at Bimota Spirit offers newly manufactured crankcases that fix this issue and allow you to rebuild the V-Due into the screaming sport weapon it was meant to be. If only Bimota had known

Makes sense right?! Erratic power delivery with injection or carbs...
He has cast his own case halves to accept a proper beefy 2-stroke crank seal and offers them for sale separately or will rebuild your entire engine.

https://www.youtube.com/watch?v=MyvF-1c7JWg
http://rideonboard.net/onboard-the-bimota-vdue/

[TZ350]

Page .... 1610

Some Bucket racing videos


first go at loading a video .hope it works. https://youtu.be/xKDeYTDpFQQ


takeing on the new master https://youtu.be/kfuTSGSw1Ls
I need to get fit lol

https://youtu.be/hxMFqtTYjr4


race 3 , kerry going to do 2 as computer is leaveing the nice sound of a 4 stroke out:devil2:
https://youtu.be/Ez-0gkrCQWwmy bike is slow


http://www.mylaps.com/en/events/1231427mixed results


Hope this is the right one. Race two. Run over Pumba...:nono:


https://youtu.be/f6RUKK88pYM


https://youtu.be/_-mLeH7qYZE
does it work , no point loading the end as video got misty . oh yes .kerry , bert , and think mr ban could not pull this off lol


you don't get this number of riders on the track at one time any more in nz
https://www.youtube.com/watch?v=gRz6HnKWnDA


Some on board from the racing. The good bits start at about 6:45 and I finally get past Regan and into 3rd place at 9:20. I had a bit of a crap start really, running the wrong gear and stuffing up lines until I set into a rhythm. Still fun and quick enough to claw back Regan. The race was 40 laps long so I cut out a bunch of sections where I'm riding by myself to fit within Youtube's 15 minute video limit.

After looking at my GPS timer, i got just over 100km at the end of the straight and was way way way to slow through the final corner at about 38km/hr mid corner, sigh. Probably after crashing there last year riding my FXR on the bumps. Theoretical fastest time was a 42.2 compared to my actual 42.599 which shows my consistency was off. I'd love to have another crack at getting into the 41s with more practice time but I'm sure there's a line from here to the GPR door with people looking for a factory ride! hahaha


https://www.youtube.com/watch?v=lpxXgx2Tf7Y


Awesome video Chris, massive ride!

Next video incoming.

Formula Penny Farthing...


https://youtu.be/tjSqknio18E


Don't get too excited, still an hour left to upload.

GP Boneshaker...


https://youtu.be/8EwKlNBTgsc


want to see race 2 of this ....https://www.youtube.com/watch?v=HcK1As59jkI


first race meet at Kaitoke on the 2 smoker.

https://youtu.be/WVmNVIHHU5E


https://www.youtube.com/watch?v=nZ5CzJco5Mw


new owner on no92 this weekend (-;
https://www.youtube.com/watch?v=IFhQzfVH4ik

https://youtu.be/bEzwfRyPLWE


Edgecumbe , race 1 .. 4 stroke , 2 stroke , 4 stroke
race 2 .. 4 stroke , 4 stroke , 2 stroke
race 3 .. 4 stroke , 2 stroke , 4 stroke

mixed weekend but the mighty 4 strokers come out on top (-;
comes to show hp can suit some tracks not others..


i like this picture
321209

Me Too ..............


https://www.flickr.com/photos/sonscc/sets/72157667478584621
some old man with the young guns

[Pursang]

I've heard all the arguments. What is the biggest problem?

We need a choice of piston & liner materials that will allow uniform(ish) circumferential expansion and a constant(ish) narrow gap within the operational range of a performance two-stroke engine. Add in piston stroke linearity, squish management, lubrication and thermal control.

In the words of a well known automotive Boof-head, "How hard can it be?".

Even if it's "rocket science", we managed to put men on the moon & brought them back, nearly 50 years ago.

I shall mention it No More, unless I've got something to run on a dyno.

Cheers, Daryl. :niceone:

quote: "Pursang is a glorious beacon of light"

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Hemi Makutu]

Ken's views are confirmed by Kevin.

www.cycleworld.com/2013/12/05/ask-kevin-why-rings-are-the-highest-flowing-heat-path-from-piston-to-cylinder-wall

( & thanks to husaberg - for his informative post about ongoing V-Due developments).

[ken seeber]

OK all you blokes, in the nicest possible voice:

"Happy birthday to you,
Happy birthday to you,
Happy birthday dear ESE,
Happy birthday to you"

8 years to the day.

Well done fellas for keeping it going and particularly to Rob for getting it going in the first place.

[Drew]

Eight years and you lot haven't moved on from the horrid two stroke shit heap.

Slow learners it would seem. Proved twice given that no one has substantially improved on anything the factories have been pumping out for decades.

[jonny quest]

There was an article done by Nasa I believe, 20 years ago, on carbon fiber pistons. I don't remember the reasons... but they were no good at the time.

The Cameron article... I knew that in F1 the clearances were basically zero for piston to cyl. And needed preheating. I had meant to bring this up to you Frits. To see if this was tried at Aprilia. I've always found just under. 002" ideal for cast 125 pistons. Never tried anything tighter.

[TZ350]

2016 Mt Wellington 2 Hour

326362

After three weeks of work on the bike in the Team ESE workshop and a last minute engine rebuild after a dyno hiccup Team Girl's Riding Fast made it to the 2016 Mt Wellington 2 Hour. The bike ran well in practice and the girls were turning in very respectable times. Times good enough to put them in a top 10 place or better.

326361

The eventual winners were Chris and Nathaniel riding 88.

326360

I didn't have a picture of second place finishers Henk and Rick but here is my favorite picture of Henk playing speed boats at an earlier wet meeting.

326363

Third place was taken by Team GPR's bike number 6. I really love the workmanship that goes into GPR's bikes and my favorite is their two stroke number 92. 92 was not run in the 2 hour, but I think 92 was run in the 40 lapper.


326364

This bike was a contender for taking out the win but after a few issues that cost them a bunch of laps, after a determined ride, finished fourth and posted another lap record on the way.

326359

What happened to the Team that brought a touch of glamour to the start grid. Well they fell victim to the carnage that seems to be feature of the first few laps of every 2 hour. By the end often the field has been cut in half by mechanical breakdowns and crashes, a two hour sprint race is a long way to survive.

Team Girl's Riding Fast made the effort to put on glum faces for the photo but they were really all smiles and enjoyed the day and cant wait to be back.

[F5 Dave]

Aww Drew. It's been a beautiful day after quite a stretch of bad weather. Why are you inside Trolling instead of outside on your glorious RF900?

[TZ350]

Eight years and you lot haven't moved on from the horrid two stroke shit heap.

Slow learners it would seem.

Two Strokers, Slow Learners, probably true that ...... :laugh: and thank you everyone for the birthday wishes.

And an especially big thank you to everyone who has contributed by posting their thoughts and interesting projects on here and all those that have enjoyed reading about them.

More Mt Wellington 2 hour stuff.

326367

My favorite picture of the day. Father daughter team and a really nicely prepared Honda.

326368

Another great 2T, ran in the 40 lapper.

326369326370

Another example of the workmanship that goes into Buckets.

326371

One of the original Honda 125T's

326372

Maybe a common Bucket of the future, fuel injected Yamaha R150's

[Frits Overmars]

We need a choice of piston & liner materials that will allow uniform(ish) circumferential expansion and a constant(ish) narrow gap within the operational range of a performance two-stroke engine. Add in piston stroke linearity, squish management, lubrication and thermal control.No choice of materials will yield a uniform circumferential expansion of the cylinder bore unless both the cylinder and its cooling are completely symmetrical. And the same goes for the piston. With exhaust gas flow on one side and incoming transfer flow on the other, you can forget about uniform expansion for both cylinder and piston.
The cylinder will even try to assume a banana shape.
I have good hopes that my FOS scavenging system will meet all requirements for symmetrical expansion but I'm not considering ringless pistons.


The Cameron article... I knew that in F1 the clearances were basically zero for piston to cyl. And needed preheating. I had meant to bring this up to you Frits. To see if this was tried at Aprilia. I've always found just under. 002" ideal for cast 125 pistons. Never tried anything tighter.That KC article needs some nuancing in the clearance department The piston to cylinder clearances are not zero in F1, but they are so small that directly after starting a cold engine the pistons may seize because they heat up quicker and thus grow more than the cylinder bores do.
Something like this was tried at Aprilia in 1993, before Jan Thiel went to work over there in 1995. Jan and myself were present working on a different marque, when an Aprilia works rider come to us for advise. His works bike kept seizing although he had meticulously obeyed the prescribed 0,03 mm cold clearance. We told him to double that, but Aprilias technical director threw in his veto. After Jan Thiels arrival at Aprilia, clearance rose to 0,07 mm.

[adegnes]

I'm going to try the 24/7 on a 50cc derbi I just aquired. Typical swinging reed system. That engine is going to be kind of a "test bench" for stupid/not so stupid ideas.
Anything special I need to consider carb wise? Easy enough to make it work in both reed/no reed state?
Happy birthday ESE!

New video out, crank truing.
https://youtu.be/X34qMzEjOnY


https://www.youtube.com/watch?v=X34qMzEjOnY

[Pursang]

:niceone:
No choice of materials will yield a uniform circumferential expansion of the cylinder bore unless both the cylinder and its cooling are completely symmetrical. And the same goes for the piston. With exhaust gas flow on one side and incoming transfer flow on the other, you can forget about uniform expansion for both cylinder and piston.
The cylinder will even try to assume a banana shape.
I have good hopes that my FOS scavenging system will meet all requirements for symmetrical expansion but I'm not considering ringless pistons.

All good points Frits, I was developing some ideas to address those kinds of issues.
Perhaps circumferential cooling of the exhaust duct(s) and a flexible exit through the water jacket could maintain some dimensional stability and help fight bananas.:wari:

Soberly 'looking forward', without the rush of excitement at getting to the end of the thread, the only financially viable use of low friction, very high speed, two-stroke engines might be powering compact generators to quickly recharge the batteries of electric race bikes, where mains power is not available.

And Hxxxa will then organise a way to have them banned from the pits anyway on noise & environmental grounds.
Hxxxa 4T generators & approved china clones permitted only. Perhaps tuning those will be where the kicks are.

Cheers, Daryl. :niceone:

[Frits Overmars]

I'm going to try the 24/7 on a 50cc derbi I just aquired... Anything special I need to consider carb wise? Easy enough to make it work in both reed/no reed state?Carb-wise there are no special requirements. But I've got some other pointers for you.
Try to accommodate the 24/7-housing in the reed cavity of the crankcase, so you can switch between both systems. Then, build and run the engine with a normal reed, so you can be sure that there are no hidden problems.
The necessary inlet tract length depends on crankcase volume, carb diameter and rpm of maximum power. This rpm is established by the cylinder's angle-areas,
so it is more or less fixed, and also there's only so much you can do to enlarge the crankcase volume, but you are free in your choice of carb diameter.
As a guideline, try SQRT(cylinder capacity x rpm of max.power / F). This factor F should be about 1200 (for conventional inlet systems F should be about 900).
This set-up will leave the inlet tract length as the value to play with. And it may need to be quite long, maybe 350 mm from carb bellmouth to 24/7-flap,
and even longer if you use a big carb, so it will be wise to allow for quickly-exchangeable distance pieces.


New video out, crank truing.Alex, that bolted-together accessory that you used to explain the effects of twisting, is a great idea to make clear what is going on.

PS: If you over-pinched your crankshaft, you can of course open it up again with a chisel and a hammmer, but I prefer to use a 'reversed vice'. That's just an M8 or M10 bolt, shortened so much that it will fit between the crank webs, and a nut. Unscrewing the nut will give you much more control than hitting the chisel with a hammer.

PS2: I suppose it's past sunday over there, but anyway: Happy Birthday ESE!

[Drew]

Aww Drew. It's been a beautiful day after quite a stretch of bad weather. Why are you inside Trolling instead of outside on your glorious RF900?

I wasn't trying to troll. I wanna see these one off things screaming and reliable.

A clever engineer friend and I are working on a two stroke design too. Once we've got that VT headed XL125 motor running and my chair back together of course.

[adegnes]

Carb-wise there are no special requirements. But I've got some other pointers for you.
Try to accommodate the 24/7-housing in the reed cavity of the crankcase, so you can switch between both systems. Then, build and run the engine with a normal reed, so you can be sure that there are no hidden problems.
The necessary inlet tract length depends on crankcase volume, carb diameter and rpm of maximum power. This rpm is established by the cylinder's angle-areas,
so it is more or less fixed, and also there's only so much you can do to enlarge the crankcase volume, but you are free in your choice of carb diameter.
As a guideline, try SQRT(cylinder capacity x rpm of max.power / F). This factor F should be about 1200 (for conventional inlet systems F should be about 900).
This set-up will leave the inlet tract length as the value to play with. And it may need to be quite long, maybe 350 mm from carb bellmouth to 24/7-flap,
and even longer if you use a big carb, so it will be wise to allow for quickly-exchangeable distance pieces.

Thank you for the advice! A good idea to establish a baseline with the conventional reed setup.
I'll get to it as soon as the Spx engine is in one piece again.




Alex, that bolted-together accessory that you used to explain the effects of twisting, is a great idea to make clear what is going on.

Thanks!
I always manage to confuse myself with where to hit when...




PS: If you over-pinched your crankshaft, you can of course open it up again with a chisel and a hammmer, but I prefer to use a 'reversed vice'. That's just an M8 or M10 bolt, shortened so much that it will fit between the crank webs, and a nut. Unscrewing the nut will give you much more control than hitting the chisel with a hammer.


That's great advice, thanks!
Reminds me of when I had spent hours trying to pound out the stator in the motor I use for my dyno, each hammer blow moved it 0.5mm or so. Halfway there I realized I could use a screw type car jack and get the job done without breaking a sweat.

[richban]

I wasn't trying to troll. I wanna see these one off things screaming and reliable.

Well you will see them at the Suzuki Series Drew. Screaming yes, Reliable Yes, Really really fast, Yes! I had the first shake down laps on the new 300. I say new as the list of parts changed sure made it feel like a new bike. On the engine side it got New Carbs, crank seals, V force reeds, total loss, electric water pump and R6 raditor, and the big one new pipes. On the chassis side new lighter wheels. KTM 690 duke wheels are very light. I dropped a rotor and caliper and replace it with New Brembo M50 single caliper and RCS master cylinder. New ali sub frame. It is so crazy fast. I will post some pic's when I get a mo.

[bjorn.clauw.1]

That's great advice, thanks!
Reminds me of when I had spent hours trying to pound out the stator in the motor I use for my dyno, each hammer blow moved it 0.5mm or so. Halfway there I realized I could use a screw type car jack and get the job done without breaking a sweat.

Hi adegnes, been looking through your videos. Really enjoyed them. On your dyno, I noticed you use an inductive pickup on your ignition lead of the engine to measure rpm via arduino. Do you have some more info on the circuit used? My rpm signal comes from my crank pickup but it would be nice if i could graph the ignition curve realtime (to confirm my programmed values)

[Drew]

Well you will see them at the Suzuki Series Drew. Screaming yes, Reliable Yes, Really really fast, Yes! I had the first shake down laps on the new 300. I say new as the list of parts changed sure made it feel like a new bike. On the engine side it got New Carbs, crank seals, V force reeds, total loss, electric water pump and R6 raditor, and the big one new pipes. On the chassis side new lighter wheels. KTM 690 duke wheels are very light. I dropped a rotor and caliper and replace it with New Brembo M50 single caliper and RCS master cylinder. New ali sub frame. It is so crazy fast. I will post some pic's when I get a mo.
Interesting. From what I saw on Friday, reliability seemed to still be elusive. Unless that was a different white NSR of course

[Flettner]

I've heard all the arguments. What is the biggest problem?

We need a choice of piston & liner materials that will allow uniform(ish) circumferential expansion and a constant(ish) narrow gap within the operational range of a performance two-stroke engine. Add in piston stroke linearity, squish management, lubrication and thermal control.

In the words of a well known automotive Boof-head, "How hard can it be?".

Even if it's "rocket science", we managed to put men on the moon & brought them back, nearly 50 years ago.

I shall mention it No More, unless I've got something to run on a dyno.

Cheers, Daryl. :niceone:

quote: "Pursang is a glorious beacon of light"

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

The sleeve engine is ringless (on the sleeve to block), as in the RR Crecy. Sleeve is supposed to expand until it transfers enough heat to the block then, shrink slightly, supposed to maintain a constant clearance. can you believe that?

[adegnes]

Hi adegnes, been looking through your videos. Really enjoyed them. On your dyno, I noticed you use an inductive pickup on your ignition lead of the engine to measure rpm via arduino. Do you have some more info on the circuit used? My rpm signal comes from my crank pickup but it would be nice if i could graph the ignition curve realtime (to confirm my programmed values)

Thanks!
Here's the circuit diagram for my arduino dyno shield:

http://s8.postimg.org/7qius0qv9/rev10_schem_schem_20160203111432718.jpg

The ignition pickup circuit is basically the same as used by Sportdevices, but with more decoupling.

http://www.sportdevices.co.uk/rpm_readings/index.htm

[bjorn.clauw.1]

Thanks, this will be a big help!

[bjorn.clauw.1]

+1 on your crank truing vid. I made a jig that holds the crank webs in allignment when I press. I normally put some green loctite in the holes in the crankwebs (a little, so there is no exces that comes out and glues your big end solid,... don't ask). They always come out true. Until last, when the pressure gage of my hydraulic press broke and I decided to eyeball it. pushed too hard and had misallignment. Frits his method with the bolt worked nicely. The axial missaligment was an other story. Gently tapping was no longer enough to adjust it. Got it true in the end though.

Wondering if it's a good idea now to put some loctite in the holes on the crankweb (or if it even helps at all)? Comes from a rotax manual I believe.

jig looks like this

326376

this looks interesting. Never tried it though. (maybe beef it up a little)

326377

[Pursang]

The sleeve engine is ringless (on the sleeve to block), as in the RR Crecy. Sleeve is supposed to expand until it transfers enough heat to the block then, shrink slightly, supposed to maintain a constant clearance. can you believe that?

Well, Eddie Gass (great name) , RR & I could. What did you find?

Cheers, DJ

Pursang is no longer "a glorious beacon of light".:thud:

"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.

[Pursang]

Here is some real good information, from a company that has been around engines for a while.

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Rings+%26+skirt.JPG

Friction power loss from piston skirt contact is 15 or more times greater than that from the rings.

And they are talking about a piston like this:
https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/4T+3Ring+circus.JPG
4T and 3 rings and a tiny little skirt that wouldn't cover a decent exhaust port (or pair of knickers).

Conclusion 1: Ringless IS Too Hard for the benefit achieved.
Coaxial/Linear/non-contact piston motion is a Winner.

Conclusion 2: If we only spoke of what we Know, instead of what we Think....The Internet would be a very quiet place.

Cheers, Daryl:niceone:

First they tell you you're wrong, and they can prove it....and they Were Right.
Daryl Jones

[Hemi Makutu]

The sleeve engine is ringless (on the sleeve to block), as in the RR Crecy. Sleeve is supposed to expand until it transfers enough heat to the block then, shrink slightly, supposed to maintain a constant clearance. can you believe that?

See post # 24118 for the patterns.

I mean - as cut into the outer face of the steel sleeve, or alternatively on the barrel it rides in, as a tribology aid.

In fact, that research mob I linked earlier, who are doing tribology-based diamond-like surface self-coating tech,
- might well be interested in a trial of it - in your hard-duty S-V application too, Flettner.

[TZ350]

Thanks Daryl, interesting, I did,t know the skirt friction was so much compared to the ring.

[Hemi Makutu]

Yeah Daryl, those super high rpm 4T pistons running extreme bore to stroke ratios have plenty of issues which don't apply to 2Ts..

These self-defeating frictional/pumping losses were part of the reason F1 went to high efficiency forced induction..

[Pursang]

Thanks Daryl, interesting, I did,t know the skirt friction was so much compared to the ring.

Neither did I, but I'm sure someone did.

Quick easy dyno experiment: 1X used piston, cut a ring groove around the skirt, shouldn't need a full skirt because it's below the ports & not holding any pressure, just the skirt off the bore. Fit a worn in/out ring, check that it doesn't drop out the bottom of the liner, check ring gap through stroke & pin it to prevent rotation.

Easier than most things you have tried.

PS, don't expect it to last too long and don't use your good barrel.

cheers, Daryl.

[tjbw]

Here is some real good information, from a company that has been around engines for a while.

....



If the top ring friction force is nearly 50N at TDC how can the ring power loss at TDC be zero?

[Pursang]

Yeah Darryl, those super high rpm 4T pistons running extreme bore to stroke ratios have plenty of issues which don't apply to 2Ts..

These self-defeating frictional/pumping losses were part of the reason F1 went to high efficiency forced induction..

I'm pretty sure F1 are told what type of engines they Must use?

But yes, those F1 strokes were Very short.
Comparatively long stroke 2T's will experience significant friction losses at lower piston speeds.
The Ricardo info was based on sports racing engines, not F1.

The friction issue is due to asperity (roughness).
Four strokes have their smooth liners 'wiped clean' by the oil rings each stroke.
Two strokes have all sorts of crap & particles passing in and out the ports and sticking into the piston surface.

Cheers, Daryl.

[Pursang]

If the top ring friction force is nearly 50N at TDC how can the ring power loss at TDC be zero?

Power =work done / time

= force X distance / time

= force X velocity

= 50 X 0

=0

The friction power loss is greatest when the piston is moving fastest. Zero when it's stationary.

Cheers, Daryl

[Hemi Makutu]

F1 changed from super-expensive, fragile/wasteful ultra-high rpm N/A V10/V8 mills to a design concept
that would appear to be more durable/efficient, the lower rpm hybrid turbo-compound...

Cost however, of making such engines hack high heat/pressure - instead of rpm, remains real high.

Fact is, 4Ts 'Have one power stroke, then three to wear the engine out' - to paraphrase R-R engineer Stanley Hooker.

To get 4Ts to do some decent work, you have to rev their tits off, or supercharge them, (chemically &/or by pumps),
which always ends up being a complex/costly exericise..

[Pursang]

F1 changed from super-expensive, fragile/wasteful ultra-high rpm N/A V10/V8 mills to a design concept
that would appear to be more durable/efficient, the lower rpm hybrid turbo-compound...

Cost however, of making such engines hack high heat/pressure - instead of rpm, remains real high.

If I had my way they could still be using old 4cyl BMW road car engines if they wanted and whatever aerodynamics & tyres they think work best.
Formula Libre is #1 for me:first:


Fact is, 4Ts 'Have one power stroke, then three to wear the engine out' - to paraphrase R-R engineer Stanley Hooker.

:clap: Wise man, and clearly seen in the Ricardo graphs.

Cheers, Daryl.

[Hemi Makutu]

A compact expansion chamber using "large angle diffuser" ( LAD) multiple internal cone flow vectoring, perhaps?

Anyone game to try it?

www.chengfluid.com/flow_conditioner/

[Pursang]

Quick easy dyno experiment: 1X used piston, cut a ring groove around the skirt, shouldn't need a full skirt because it's below the ports & not holding any pressure, just the skirt off the bore. Fit a worn in/out ring, check that it doesn't drop out the bottom of the liner, check ring gap through stroke & pin it to prevent rotation.

Easier than most things you have tried.

PS, don't expect it to last too long and don't use your good barrel.
.

Quick easy experiment #2. If you're uncomfortable with adding a ring to the bottom of a piston, you could do a quick and dirty run with these.
https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/ball+b.JPG

Hole in skirt (front & rear) to let ball protrude. Countersunk brass screws & nuts to adjust. (Could also add some springs or rubber, for a tiny bit of pre-load). Should roll in and out (over/through?) inlet/transfer ports, if required. Or use 2 one on either side of port or piston cut-out.

Similar PS applies: don't expect it to last for more than a couple of minutes and don't use your good engine.:nono:

A couple of back to backs (without & with) should disclose if any significant benefit is available.
(15 KW in the Ricardo tests, assume that's per piston so +66% for the 125, worth a look?)
Remember though, it was only 15KW peak at max piston speed so any improvements will be averaged.

PPS, keeping the piston square in the bore might help those Wisecos survive better too.

PM me if it works. Don't sue me if it doesn't.

Cheers, Daryl

[Hemi Makutu]

Quick easy experiment #2. If you're uncomfortable with adding a ring to the bottom of a piston, you could do a quick and dirty run with these.

Hole in skirt (front & rear) to let ball protrude. Countersunk brass screws & nuts to adjust. (Could also add some springs or rubber, for a tiny bit of pre-load). Should roll in and out of inlet/transfer ports, if required.

Similar PS applies: don't expect it to last for more than a couple of minutes and don't use your good engine.:nono:

A couple of back to backs (without & with) should disclose if any significant benefit is available.
(15 KW in the Ricardo tests, assume that's per piston so +66% for the 125, worth a look?)

PM me if it works. Don't sue me if it doesn't.

Cheers, Daryl


Fit the brass ball/roller nibs in the thrust face & pre-load with lube, instead of ink?

[Drew]

Neither did I, but I'm sure someone did.

Quick easy dyno experiment: 1X used piston, cut a ring groove around the skirt, shouldn't need a full skirt because it's below the ports & not holding any pressure, just the skirt off the bore. Fit a worn in/out ring, check that it doesn't drop out the bottom of the liner, check ring gap through stroke & pin it to prevent rotation.

Easier than most things you have tried.

PS, don't expect it to last too long and don't use your good barrel.

cheers, Daryl.How do you lubricate the piston/sleeve?

[Flettner]

Now your just taking the piss. :eek:

[adegnes]

+1 on your crank truing vid. I made a jig that holds the crank webs in allignment when I press. I normally put some green loctite in the holes in the crankwebs (a little, so there is no exces that comes out and glues your big end solid,... don't ask). They always come out true. Until last, when the pressure gage of my hydraulic press broke and I decided to eyeball it. pushed too hard and had misallignment. Frits his method with the bolt worked nicely. The axial missaligment was an other story. Gently tapping was no longer enough to adjust it. Got it true in the end though.

Wondering if it's a good idea now to put some loctite in the holes on the crankweb (or if it even helps at all)? Comes from a rotax manual I believe.

jig looks like this

326376

this looks interesting. Never tried it though. (maybe beef it up a little)

326377

Thanks!
......

[Pursang]

How do you lubricate the piston/sleeve?

Piston & liner will be exposed to air/fuel/oil through the inlet & transfer ports.
Fuel vaporises and leaves some oil behind.
Doesn't need much cos there's bugger all contact between the piston & liner.

Remember this is just an idea for a quick dyno test. Squirt some oil on it during assembly.

Cheers Daryl.

[Pursang]

Quick easy experiment #2. If you're uncomfortable with adding a ring to the bottom of a piston, you could do a quick and dirty run with these.
https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/ball+b.JPG

Hole in skirt (front & rear) to let ball protrude. Countersunk brass screws & nuts to adjust. (Could also add some springs or rubber, for a tiny bit of pre-load). Should roll in and out (over/through?) inlet/transfer ports, if required. Or use 2 one on either side of port or piston cut-out.

Similar PS applies: don't expect it to last for more than a couple of minutes and don't use your good engine.:nono:

A couple of back to backs (without & with) should disclose if any significant benefit is available.
(15 KW in the Ricardo tests, assume that's per piston so +66% for the 125, worth a look?)
Remember though, it was only 15KW peak at max piston speed so any improvements will be averaged.

PPS, keeping the piston square in the bore might help those Wisecos survive better too.

PM me if it works. Don't sue me if it doesn't.

The screwed on ball bearings might be a bit rough, even for me.:scratch:

How about Brass brake shoe rivets? Brass Thumb tacks?

How about Teflon buttons, shaped like thumbtacks, countersunk into the skirt?

Quick & easy to do, should give enough life for a few runs before it all turns to poo.
Works for Harleys on Nitro.

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/bulpstn_peek1.jpghttps://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/bulpstn_peek2.jpg

Credit for the pics to this site: https://www.rbracing-rsr.com/bulbenefit2011.html

Cheers, Daryl

[rgvbaz]

326268



Cant see it in the picture but the exhaust fan has been put inside a piece of air duct that used to go around a pot belly stove chimney. The fan itself is a 200mm 400V 3 phase unit a friend rescued from the skip for me so I don't really know where you could buy one. Behind Cully is another 200mm fan that draws fresh air from outside and blows it over the dyno operators.

For an exhaust extractor fan, the gutted propane heater looks a very good idea.


I'm using a gutted propane heater, works ok(for 50cc atleast).
http://www.masterheaters.com/Desa_images/blp375t.jpg

I've actually got a proper exhaust extraction fan, but that's used for cooling. When I think about it my bike always seems to be "overcooled" on the dyno, might switch them around.

http://img.directindustry.com/images_di/photo-g/13788-8404734.jpg


Thanks for the info guys.

A few pics of our dyno:

326406326405326407

Dave

[adegnes]

Thanks for the info guys.

A few pics of our dyno:

326406326405326407

Dave

That's a nice clean looking dyno, especially found of the front wheel mount!

How about some "slow tv" to round off the evening.

https://youtu.be/hlsogG-zcC0

https://www.youtube.com/watch?v=hlsogG-zcC0

[jonny quest]

Tell me what you used for inertia wheel on your dyno

[rgvbaz]

That's a nice clean looking dyno, especially found of the front wheel mount

Cheers adegnes :)

[rgvbaz]

Tell me what you used for inertia wheel on your dyno

Assume this was for me?

The wheel was from another dyno... I believe a guy made a few of these quite some time ago. It really is a little too small but it is better than nothing. If we increase the gearing of our bikes it will increase the length of the runs while not exceeding the burst speed of the roller (according to my calculations!?)

Idealy I would want to upgrade to this at some point: http://www.dynomet.dk/en_diydynoparts.htm

The dyno chassis can easily be modified to accept the dynomet roller.

Dave

[peewee]

You probably can match the squish to the piston dome.
It sounds like you have a lathe, and it probably has a swiveling toolpost, locked in place by grubscrews or a handle. Once you identify the exact radius of the piston dome, you can set the tip of the tool to be slightly less than that radius from the centre of the toolpost swivel. I say slightly less, because you want to avoid a negative squish angle (=deto), so the squish band radius needs to be a little tighter to produce a positive (diverging) or neutral squish angle.
Then with the grubscrews or handle loosened, you just swivel the toolpost assembly back and forth by hand, taking tiny cuts (since it won't be mechanically controlled). Works a treat.

Hardest part is identifying the exact centre of the toolpost pivot. Piston dome radius can also be tough to determine as some aren't a pure spherical cap.

Obviously this technique won't be feasible if the dome radius is more than about 100mm.

the problem is the local machinist does mostly automotive stuff and says he cant do a radius in the head band. either he doesn't know how or his machine isn't capable. so for now I wont have a radius in the head band until I can send the head off to someone else. heres what I have since the last bit of cutting.

1- band width 16mm , bore 91mm = 58% of total area. to get this closer to 50% I need to be about 13mm wide.

2- piston gap at bore edge is 1.34mm- 1.58mm going toward center at 16mm. if I cut the band width to 13mm ill have 1.34mm-1.48mm because the flat head band and radius piston

3- piston at tdc I was only able to fill with 27cc oil which gives 20.5 comp ratio , 528+27/27. far to high im thinking. increasing it to 34cc would give 16.5 and this is likely better maybe. even for methanol. then again I haven't a clue what im doing

4- the plug is now much closer to the piston top but I will have to check that tomorrow. didn't wob say this is not important ?

5- local guy says he should be able to cut into the bowl if its a true hemi shape but anything like a bathtub style is totally out of the question

6 - so is there any easy way to figure how much volume ill gain by cutting the band 3mm narrower. so I end up with 13mm wide (50% approx) and 7cc more than I have now ? this is getting a real pain in the neck :brick:

oh one more question. originally the head used bolts going into the cylinder. ive since installed studs and will clamp it with nuts. do you reckon the torque value should still be about the same or close ?

[Ocean1]

originally the head used bolts going into the cylinder. ive since installed studs and will clamp it with nuts. do you reckon the torque value should still be about the same or close ?

Bit less torque required on the nuts to get the same clamping force, there's just less friction from surface area with studs/nuts than there was with bolts. Can't help with exactly how much less though.

The best measure of the clamping force is bolt/stud elongation, and it's not unusual on critical applications to torque fasteners to a set elongation. However, unless you can get a micrometer over the full length of the fastener that's difficult to do, you can use a DTI on studs but as you're supposed to torque each stud incrementally in turn you'd have to set up a parallel bar over a reference face to measure from.

[peewee]

original bolt torq was 25 lbft. 2-3 lbft less should do the trick. good news is it held 20 lbft in a static condition last night with out pulling the studs from the cylinder. I severly over heated the cylinder during welding so im a bit nervous. not to mention I welded for hours on it :laugh:

[Frits Overmars]

piston gap at bore edge is 1.34mm- 1.58mm going toward center at 16mm. if I cut the band width to 13mm ill have 1.34mm-1.48mm because the flat head band and radius piston.That's not a squish gap but a deto gap. If you reduce it to half of what it is now, it will raise the compression even further but it will nevertheless reduce the deto risk.


the plug is now much closer to the piston top but I will have to check that tomorrow. didn't wob say this is not important ? He did, and so do I.


local guy says he should be able to cut into the bowl if its a true hemi shape but anything like a bathtub style is totally out of the question.If he can cut a hemi shape, he can also cut an off-center hemi shape which is what you need, or you'll never approach the required volume.


originally the head used bolts going into the cylinder. ive since installed studs and will clamp it with nuts. do you reckon the torque value should still be about the same or close ?I'm not so much worried about the studs, but what about the strength of the head itself? If you remove the required volume, will it still be strong enough for that methanol-compression?


is there any easy way to figure how much volume ill gain by cutting the band 3mm narrower. so I end up with 13mm wide (50% approx) and 7cc more than I have now ?use this: 326423

It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape.
I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card.
I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
And in case you are using Windows 10: may God have mercy on you.

[adegnes]

I've reshaped/resized combustion chambers and cut new squishbands with an electric hand drill clamped in the vice, a dremel, files, and sandpaper glued to a piston.
Not the most precise method, but it works ok.
Great idea for a poor mans how to video I think!

[breezy]

I've reshaped/resized combustion chambers and cut new squishbands with an electric hand drill clamped in the vice, a dremel, files, and sandpaper glued to a piston.
Not the most precise method, but it works ok.
Great idea for a poor mans how to video I think!

Yes id love to see that... cause im really poor:weep:

[F5 Dave]

Well an extraction fan fell into my hands last night. Its only a pitiful 150mm unit but its got to be better than nothing i can'tsee it being a rrestriction. Now Ijust need to score some flexible ducting and think of a decent way to hold it near the exhaust without it getting snagged by the rear wheel spinning on the dyno roller.

[Drew]

Well an extraction fan fell into my hands last night. Its only a pitiful 150mm unit but its got to be better than nothing i can'tsee it being a rrestriction. Now Ijust need to score some flexible ducting and think of a decent way to hold it near the exhaust without it getting snagged by the rear wheel spinning on the dyno roller.
I've got ya covered for ducting.

[lodgernz]

use this: 326423

It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape.
I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card.
I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
And in case you are using Windows 10: may God have mercy on you.

Seems to run on Win/2000 too, but returns an error message "no cylinder head files found. press Enter to continue".
Pressing Enter then exits the program.
Something missing?

[jfn2]

What is the correct distance down the pipe from the piston to install a egt sensor? I've heard 200mm.

[peewee]

That's not a squish gap but a deto gap. If you reduce it to half of what it is now, it will raise the compression even further but it will nevertheless reduce the deto risk.

He did, and so do I.

If he can cut a hemi shape, he can also cut an off-center hemi shape which is what you need, or you'll never approach the required volume.

I'm not so much worried about the studs, but what about the strength of the head itself? If you remove the required volume, will it still be strong enough for that methanol-compression?

use this: 326423

It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape.
I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card.
I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
And in case you are using Windows 10: may God have mercy on you.

thnx for the help frits. I have win7 so ill give it a try. I was worried about how thick the chamber was since I cut quit far into it. originally I was going to drill a hole and measure thickness then weld the hole shut but I forgot. whats the worst that could happen now, chamber cracks and I lose some water into the cylinder and it smokes more than normal :laugh: . im sure the methanol would be happy at 20/1 but the engine probly wouldn't and wouldn't that high comp ratio put a damper on the rpm limit and cause who knows how many other problems ? the local machinist doesn't have a cnc that I know of but I have some other people out of town I can send it off to. first ill talk to the local guy and see if theres any way he can do it

[Hemi Makutu]

P-W, try flicking an email to this bloke: www.twostrokeperformance.com.au/measuring-squish-clearance/

Dave does re-profile quite a few KTM 2T heads, & has done some monster 2T cylinder dirt bikes too..
& as a helpful enthusiast, he'll likely give you some pointers of value..

[peewee]

nice idea but with my luck it would get lost in customs and I have to start over with a part that's already rare as hens teeth. try finding a ktm500 head before july

[Frits Overmars]

use this: HEAD.zip. It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape. I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card. I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
Seems to run on Win/2000 too, but returns an error message "no cylinder head files found. press Enter to continue". Pressing Enter then exits the program. Something missing?Yep. I forgot to add a HEAD data sample. I could send one, but first I'll try to write an improved version of the HEAD-program that will deal with this data-less situation. I'll be back.

EDIT: this should do it: 326435

Please let me know if there are any more problems. That HEAD-program should behave now. It was not initially meant to stand-alone; it was part of a bunch of programs that I am planning to make available to you guys, but that will still take some testing.

[jfn2]

"That HEAD-program should behave now. It was not initially meant to stand-alone; it was part of a bunch of programs that I am planning to make available to you guys, but that will still take some testing."

Now that is GREAT news!

[wobbly]

If the geometry is calculated correctly there is no need to produce a radiused squish to follow the piston at all.
Here is a 50% squish on a 66 piston with only a tiny amount of divergence using a simple straight cut.

Also a pic of the special CPI cylinders I had cast for Charletts new 400 Superlight, brought them home in my bag from Vegas.
The first oval ports they have done.

[WilDun]

If the geometry is calculated correctly there is no need to produce a radiused squish to follow the piston at all.
Here is a 50% squish on a 66 piston with only a tiny amount of divergence using a simple straight cut.

Is there a reason for the piston crown (squish area) to have a curve at all?

[wobbly]

No reason at all.
Most all the Italian 125 race engines have a conical dome shape ( 4* or 7* ) , so the squish could match perfectly.
VHM make a flat top with a radius on the timing edge that makes more power,but I believe the perfect setup would be the radius combined
with a conical the same width as the squish, then a flat top.
This may not in fact be the best for a KZ engine , as I found that a flat top is only superior when combined with a proper toroidal chamber, and this cant be done
in this class due to the way the compression cc is checked,simply filling to the top plug surface.

But in any other engine I would bet a few dollars that the radius/conical/flat top/toroidal hybrid would show the best result overall.
The SwissAuto/Pulse engine had sort of this setup using a stock radiused RS125 dome, but the non squish area of the piston was machined flat, as did the BSL500
that had a straight conic squish and a flat top with a toroidal.

Flat top pistons are technically strictly speaking not as strong under the compression UDL, but if the tune is wrong and the dome collapses a little, then that piston immediately traps the ring.
A flat top will collapse a little, but then doesnt trap the ring,causing a DNF.

[Haufen]

Wobbly, what do you say about the "bimotion type" squish band, taking the area the gases have to pass through into consideration?

point 3 lower column red and blue line
further explanation in 3.1

in this link here (http://www.bimotion.se/Theory/Theory.html)

Sounds reasonable to me from a theory point of view.

[wobbly]

I totally disagree with a diverging squish gap.
There are three considerations.

1st. Is the trapped end gas volume.This is minimized with a parallel squish gap.
A diverging angle has greater volume so contradicts that rules requirement.

2nd. The gap at the chamber edge sets the squish velocity number, not that at the bore face.So a diverging squish angle has less effective velocity.
This effect is only useful if having a low MSV is what is needed to reduce chamber turbulence ( as is the case with a straight line ignition, and we threw those in the rubbish a century ago ).

3rd. One of the main reasons for having a minimal squish height ( determined by the mechanical limit of the piston contacting the head ) is to keep the piston cooled as much as possible
by the heads boundary layer close to the water cooled squish band.
A tapered squish doesn't conform to this rule either.

I have no way of confirming the theory, but I know of a couple of very clever 2T engineers that have access to all the equipment and CFD software, and they are
adamant the squish rotation is in the opposite direction to that shown.
But aside from that the theory of a thick boundary layer in the corner of a " bathtub " chamber coincides with the dyno work of Jan Thiel at Aprilia using a domed piston.

It could also be one reason a proper toroidal chamber works so well, as it too would have an area of high boundary layer thickness in its chamber roof.
Despite technically having greater surface area over a bathtub or a simple spherical chamber shape.

One last point now that I have seen the old dumb - arse idea brought up again, is that having " slots " in the squish-band, straight, radial or whatever, contradicts all of the above rules.
This CAUSES detonation, and where has ANYONE published a back to back dyno comparison to show ANY positive effect from this idea that may seem clever, but simply is not.

[Muciek]

Wobbly what kind of gains do You expect to get from those cylinders compared to the last 400 cc bike You build (96hp aprilia chassis)?

[peewee]

If the geometry is calculated correctly there is no need to produce a radiused squish to follow the piston at all.
Here is a 50% squish on a 66 piston with only a tiny amount of divergence using a simple straight cut.

Also a pic of the special CPI cylinders I had cast for Charletts new 400 Superlight, brought them home in my bag from Vegas.
The first oval ports they have done.


the gap may be a bit excessive right now but once I cut the width down to 13mm (50%) then ill have nearly a parallel gap or close enough I guess anyways. outer 1.35mm/ middle 1.33mm / inner 1.47mm. rather than fooling with a radius band maybe it would be better if I just try to get the band down to 50% and get the comp ratio alittle lower and try it

the cylinders look nice. I hope its just a small batch for yourself and close friends. other wise every tom dick and harry banshee tuner will likely end up with a set and surely claim the idea as their own :laugh:. hek I would even be becareful posting photos. its one thing to copy a idea for personal use but a lot of them guys have shops and use copied ideas to make money.

hey while I think of it, did you do anything different at the front of A , so you could get more of a rsa type of aux shape ? I always wondered if the square A and square aux were something that could be improved or not. either way good luck and let us know how they go. if my frankerstien yami twin cylinders turn out like piss I may need to try some of yours :Punk:

[wobbly]

Maybe the new Superlight 400 will crack 100RWHp but I am not looking for ( or need ) more peak power, but just wanting to add to the front side
for acceleration.
The cylinders were cast off special cores made for me from my CAD files, so no one else has access to the changes, and for example the bottom of the Aux port cores were hand scraped
enabling enlarging to the ideal teardrop shape by hand grinding before plating.
This was also extended to enlarging the water jacket sides so I can grind the Aux ducts right up to the flange like an Aprilia.
Lastly the curved powervalve slots will be CNC cut here, so even CPI cant simple copy this technology for others.

[Grumph]

Also a pic of the special CPI cylinders I had cast for Charletts new 400 Superlight, brought them home in my bag from Vegas.
The first oval ports they have done.

No welding to leak on those ones ? Lucky Dennis.....

[F5 Dave]

Still have to be sound after machining. So CPI are still going sans Calvin?

Just restarting my 496. Found the pvs weren't playing to the same tune the servo pulley was.

[wobbly]

Yep, CPI is now being run by Calvins wife.
I had endless arguments with Calvin over 2T theory, so things were a bit strained sometimes, but he was an absolute casting maestro.
His wife and her new tech/shop team are more than amenable to making my changes, and I was
real lucky to be able to piggyback onto an order of 20 stock Cheetah cylinders for another big USA customer.
These new castings are porosity free, the machined bore looks like its chromed already, plus the area in the Ex port that was prone to leaks is now 5mm thicker - so I dont see any issues there.

I have subsequently " fixed " the weld leaking problem with the pre 82 TZ400, but that doesnt reduce the piss off from the Sheene meeting.
Dennis smoked them ( and pre 89 ) in practice and easily won the first heat, so he was super gutted about the reliability issue,but I am even more pissed
as my bikes have easily won that title 4 years in a row.

[Sketchy_Racer]

Maybe the new Superlight 400 will crack 100RWHp but I am not looking for ( or need ) more peak power, but just wanting add to the front side
for acceleration.
The cylinders were cast off special cores made for me from my CAD files, so no one else has access to the changes, and for example the bottom of the Aux port cores were hand scraped
enabling enlarging to the ideal teardrop shape by hand grinding before plating.
This was also extended to enlarging the water jacket sides so I can grind the Aux ducts right up to the flange like an Aprilia.
Lastly the curved powervalve slots will be CNC cut here, so even CPI cant simple copy this technology for others.

100whp in a 130 something kg bike that is setup well will smash not only F3 lap records, but also threaten F2 lap records. I know for a fact that a 1:08.5 is possible around Manfeild with 100hp in a 165kg bike and a 1:07.5 with 115hp and 160kg

Keeping in mind that the current lap record is 1:12.0 for F3 at manfeild it's going to be fuckin awesome to watch!!

[EssexNick]

Sorry to drag this thread back to earlier posts (342 on), but it looks to me like an oil cooler for the gearbox. Would the reduction of transmission losses justify the added complexity/weight/increased load on the engine?
I'm thinking of buckets at this point.

[husaberg]

Sorry to drag this thread back to earlier posts (342 on), but it looks to me like an oil cooler for the gearbox. Would the reduction of transmission losses justify the added complexity/weight/increased load on the engine?
I'm thinking of buckets at this point.

http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130173462#post1130173462
It could be but it only appeared on that model?
All the others have some plain alloy electronic looking box (not the PGM though)
Also the lines appeared to lead to it as well as the text.
Further pics and test o one here
http://www.kiwibiker.co.nz/forums/album.php?albumid=4837&page=7
Regardless it was a dead end as it was to slow in responding and getting back up to temp.

[EssexNick]

I've looked again and I'm still not sure. This just shows a lack of consideration on the part of the photographer. Or a willful desire to keep me guessing. Or my eyesight is worse than I thought.
Anyhow, elsewhere, there was also discussion of adding a sump to gearboxes. These two things led me to wonder about the merits, if any, of actively cooling the transmission oil.

[husaberg]

I've looked again and I'm still not sure. This just shows a lack of consideration on the part of the photographer. Or a willful desire to keep me guessing. Or my eyesight is worse than I thought.
Anyhow, elsewhere, there was also discussion of adding a sump to gearboxes. These two things led me to wonder about the merits, if any, of actively cooling the transmission oil.

The origional Kawasaki tandem sure benefited from the reduced spash effect when it lowered the oil level resulting in less hot oil that previously heated its crankcases from it wet gearbox.
I would say that pressure feed gearbox oiling and water cooled cases have made it a bit irelevent. When compared to the benefits offered by these other alternative solutions.
Most of the heat comes from the clutch, which ideally should be dry and air cooled anyway.
Honda deemed the pressure feed gearbox to be worth while on road bikes (nsr250) it was hardly something that most would have noticed as being race derived and a selling point, unlike the fashionable single sided swingarm , gull arm tri arms and dry clutchs etc.

[EssexNick]

Thanks for the reply. Most of what I know about two strokes is at least 25 years out of date, but I still wonder about these things.

[jasonu]

Most of what I know about two strokes is at least 25 years out of date, but I still wonder about these things.

Mate remember most 2T buckets are also at least 25 years old...

[adegnes]

https://www.youtube.com/watch?v=U2OBHpQhixE


https://www.youtube.com/watch?v=pA91yGMUIG0

That head cutting how to kinda turned into a joke... I swear it has worked great for me before....

In fact, here's a pic of a head I reshaped with this method a few years back:
326487

Not too bad I think, for what it is.

[Frits Overmars]

Alex, I very much like your down-to-earth videos that show all the little problems one can encounter.
BUT
Be extremely careful. Not because you can damage yourself but because you can easily damage the cylinder.Yes, it would be a pity if you damage that part. But you can always get another one. And the same goes for your sweater that will be grabbed sooner or later.
And the skin on your arms and hands will self-repair too, given time. But where do you plan to get a new set of eyes? For gods sake man, were some eye protection.

[adegnes]

Alex, I very much like your down-to-earth videos that show all the little problems one can encounter.
BUTYes, it would be a pity if you damage that part. But you can always get another one. And the same goes for your sweater that will be grabbed sooner or later.
And the skin on your arms and hands will self-repair too, given time. But where do you plan to get a new set of eyes? For gods sake man, were some eye protection.

Thanks!
You are absolutely right! I usually do wear protection glasses, guess I got a bit carried away...
I should know better, I've actually had an aluminum chip pulled out of my eye with tweezers by the doctor once.

[EssexNick]

Mate remember most 2T buckets are also at least 25 years old...

Exactly why I'm here. If I'm to drag the old H1 anywhere near the 21st century then this is the place to be.

[F5 Dave]

Mission 1 annoy the purists.

I see a radiator and some bucket style water jackets. :wings:

[breezy]

[QUOTE=adegnes;1131015369]
https://www.youtube.com/watch?v=U2OBHpQhixE


https://www.youtube.com/watch?v=pA91yGMUIG0

That head cutting how to kinda turned into a joke... I swear it has worked great for me before....

In fact, here's a pic of a head I reshaped with this method a few years back:
326487

Not too bad I think, for what it is.[


thanks for the video... when you have very limited equipment," a mans got to do what a mans got to do".. i recently watched a video of a man cold chiselling a keyway in a large crank shaft and thats how they used to do it for real!! no milling machines then.

[wobbly]

The new 400 Superlight for Dennis will be closer to 100Kg than 130.
It has a carbon tank and bodywork, every bolt/axle is Titanium, and small diameter front Brembo discs off Aoyama's 250GP title winning bike.
With Marchesinis all round and alot of unneeded alloy ground off the chassis it should be a rocket.
I got a Mupo suspension kit for it, to replace the internals of the 2006 HRC RS250 forks, with an all adjustable rear shock for the Aprilia chassis
but Mr Taylors dyno says they are " shocking " so they will need a lot of revalving to stop Charlett whining endlessly about the handling.

[lodgernz]

EDIT: this should do it: 326435

Please let me know if there are any more problems. That HEAD-program should behave now.

Yes that's better. It doesn't run on an HP 200LX running MS-DOS 6 BTW.

A question though about the box containing the legend "Radius 6.84" in the attached pic: Is this the radius of the curve from point 2 to point 3?
I set it at 6.5 in the parameters, but I'm guessing the program has corrected it to match the required CR?

[husaberg]

https://www.youtube.com/watch?v=U2OBHpQhixE

https://www.youtube.com/watch?v=pA91yGMUIG0

That head cutting how to kinda turned into a joke... I swear it has worked great for me before....

In fact, here's a pic of a head I reshaped with this method a few years back:


Not too bad I think, for what it is.

Chatter was one of the words you were searching for. Much like the chatter of teeth. hakke tenner
The other was method metod

[adegnes]

Chatter was one of the words you were searching for. Much like the chatter of teeth. hakke tenner
The other was method metod

Thanks!
.....

[husaberg]

Thanks!
.....

Thanks for the videos and also thanks for the Norweigan girls.

[adegnes]

Thanks for the videos and also thanks for the Norweigan girls.
:2thumbsup:2thumbsup:2thumbsup

[Frits Overmars]

Please let me know if there are any more problems. That HEAD-program should behave now.
Yes that's better. It doesn't run on an HP 200LX running MS-DOS 6 BTW.
A question though about the box containing the legend "Radius 6.84" in the attached pic: Is this the radius of the curve from point 2 to point 3? I set it at 6.5 in the parameters, but I'm guessing the program has corrected it to match the required CR?It should still run under MS-DOS 6, but some command may have crept in that is too new, so DOS doesn't recognize it. I don't have DOS at hand so I can't test it now.
You assumed correctly that your 'radius 6.84' is the radius from point 2 to point 3, and this radius is the result of a calculation; it cannot be set by the user.
The program also offers the option to enter a radius at point 2, but this radius won't be displayed in the graph (I got lazy writing the necessary extra program lines). Besides, a radius at point 2 has proved to be undesirable.

I wrote the HEAD program for my personal use, so not every option will be clear at first sight. For example, you may have noticed that some questions show a zero in front of the question mark. That zero indicates that there may be another way of answering the question. Enter the zero and the next question regarding the same item will appear. Below you can see a couple of examples.
There is also an example of a diesel-type piston crown with an intruding-plug head. I'm not advising this kind of chamber; it merely shows what the program can handle.

326501 326502 326503

[jfn2]

Hello Frits:
In your program it asks for 'squish clearance' and I set it at 1mm. Then it asks for 'squish clearance center gap' and I set this at 1mm also, but when the pic comes up it shows a squish of 0 for Z1 and a .95 for Z2. Also with a spherical topped piston I get Z3 and Z4 having the same dimension. How can this be? What am I doing wrong? Thanks

[F5 Dave]

Asking for a squish clearance of 1mm

[Frits Overmars]

Hello Frits: In your program it asks for 'squish clearance' and I set it at 1mm. Then it asks for 'squish clearance center gap' and I set this at 1mm also, but when the pic comes up it shows a squish of 0 for Z1 and a .95 for Z2. Also with a spherical topped piston I get Z3 and Z4 having the same dimension. How can this be? What am I doing wrong?You're reading things that aren't there; that's all. The Z-values have nothing to do with squish clearances. They indicate heights, measured from point 1.
Usually you set Z=0 for point 1 but if for example you want to have a head that centers in the cylinder bore, you can specify a different Z1-value, and all other Z-values will be adjusted accordingly; this will make life easier for the CNC-operator.


Asking for a squish clearance of 1mmMaybe that's wrong, maybe it isn't, Dave. I don't know the stroke of his engine. If it's 100 mm, he's doing fine with 1 mm squish :D.

[jfn2]

Thank you Frits. I now understand, mostly. I am working on an engine with a 54.5 mm stroke but I just threw in the 1mm to run the program.

[jfn2]

Bye-the-way I am using windows 10 with dosbox.

[Frits Overmars]

Bye-the-way I am using windows 10 with dosbox.Thanks for the info. I'm surprised that the program behaves under Dosbox, because that really only contains a stripped-down version of MS-DOS 5, not MS-DOS 6.
Please let me know if it will cleanly save and load the head-data that you created.

[jfn2]

No it will not cleanly load and save the new results. What I do is to use the sniping tool in windows 10 and save the data and drawing screens into a separate file. To run the same file I must reload the data. Really no problem with this small of program and files. It would be tougher with a larger program. I could relearn dos commands and save it that way and make it work. Using the split windows in windows 10 I can view both the drawing and the data screens at the same time. Thank you for the program.

[peewee]

hey wob and frits I don't have a good way to test most of this engine stuff so maybe you can answer these question. I see on a lot of oem reed blocks theres no dividers. would dividers (horizontal and vertical) be useful mostly just for when theres a kink from the carb to the cylinder, so the air doesn't get piled up on one side of the crankcase or do they have a practical purpose even on straight inlets ? further more if you split the block in four sections with dividers would it make sort of like four venturis and the air would speed up ?

other question is about the fingers and the photos attached. if you cut out four of the fingers you gain the equivalent area of adding another reed petal. but with four large petals would they require a larger negative crankcase pressure to open them ? or is it better to keep the eight smaller petals ?

[wobbly]

Currently the fastest engines use the 2 petal setup as the extra dividers for 3 or 4 per side create more turbulence ( or double that in a VeeForce )
Extending the dividers both horizontally and vertically with airfoil leading edges also decreases the flow disruption caused
when the air suddenly hits a short support close to the petal.
The 2 wide petals will be alot stiffer, so will have to be thinner ( or waisted at the clamp face ) to achieve the same lift due to case depression assisted by intake column tuning.
I have seen tests adding vertical dividers to an older VeeForce ( that already has the horizontal wing shape ) and this made better power.
Newer ( higher flowing ) versions of the VeeForce have the vertical dividers now as well.

[breezy]

"There’s very little all the factories agree on, but engine rotation is one of them After sunshine, rain and fresh air, my favourite natural phenomenon is gyroscopic effect. This is because we wouldn’t be able to ride motorcycles without it. If you don’t believe me, try this next time you’re out riding: when you stop at a traffic light, don’t put your feet down. (And don’t send me the bill.) A motorcycle’s spinning wheels create gyroscopic effect that keeps the machine going straight. The more speed, the more gyro and the more stability. This is all good, unless you are racing. Most racers don’t give a hoot about straight-line stability: they’re happy to hold on like gorillas on the straights, just so long as the bike will turn left or right in the blink of an eye. And this is why all premier-class Grand Prix manufacturers – possibly for the first time in history – now run their engines backwards. It may also explain why Marc Márquez’s COTA and Argentina victories were so huge – bigger than any dry-track wins from last year. When an engine runs forward (like most streetbikes) its crankshaft rotates the same way as the wheels, thus adding to the gyro effect, which makes it more difficult to turn into a corner or change direction. The obvious way to reduce gyro effect is to reverse the direction of engine rotation, so the reverse-rotating crank reduces the total gyro effect created by the fast-spinning wheels. The beneficial effects on the dynamics of a motorcycle are significant: 2the bike will turn quicker and change direction faster; a huge consideration in modern racing when most racetracks are very tight and twisty. A reverse-rotating engine also reduces wheelies, because the crank’s torque reaction pushes the front wheel down during acceleration, rather than lifting it (although this is less important than in the days of two-strokes, when crankshaft inertia was greater.) However, nothing is for free in racing. If you run the engine backwards the engine needs an extra jackshaft to keep the rear wheel turning the right way. That shaft absorbs a significant amount of horsepower, as well as increasing engine weight and dimensions. In theory, a reverse-rotating crank also increases understeer in corners, making the bike run wide on the exit, which can prevent the rider from getting on the throttle. But presumably all these costs are worthwhile because this year Honda reversed the engine rotation of their RC213V, the first time they’ve run an engine backwards since the days of the 500s. The last time Honda went backwards was in 1987. The first NSR500, born in 1984, was a real handful, partly because its V4 two-stroke engine ran forwards. The torque reaction from the forward-rotating crankshaft lifted the front during acceleration, causing plenty of problems for riders who spent too much time fighting wheelies instead of thinking about the next corner. The NSR ran backwards from 1987 and won eight of the last 13 500cc titles."

A bit off topic and random but...:bleh::cold:

[adegnes]

https://www.youtube.com/watch?v=KJntN-4ZrZM

[Frits Overmars]

Breezy, I agree with almost everything you wrote. But not this:
"my favourite natural phenomenon is gyroscopic effect. This is because we wouldn’t be able to ride motorcycles without it. If you want to get to the bottom of this, click these links and watch the videos till the end.
http://bicycle.tudelft.nl/stablebicycle/
http://www.youtube.com/watch?v=YdtE3aIUhbU&feature=player_detailpage
http://www.youtube.com/watch?v=84Wczsi4vHg&feature=player_detailpage


A bit off topic and random but...:bleh:I agree again. But there's an easy solution: it would be right on topic here: http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis/page56

[Drew]

"There’s very little ...."

A bit off topic and random but...:bleh::cold:
That's all very interesting, but ultimately incorrect.

What is actually happening to keep you upright, is a subtle weave from side to side. Faster ya go, the less weave is required.

The direction of rotation is of little consequence, the gyroscopic effect is the same.

Why spin the motor backwards then? Because it somewhat cancels the want of the bike to wheelie. For the front to come up, it now has to overcome the accelerating mass of the flywheel and crank, as well as the weight of the bike.

[wobbly]

The direction of crank spin has a huge influence on the bikes stability on corner entry and exit.
This is the precession effect,and we tried it experimentally when arguing about the crank spin of the BSL500 design.
Get a bicycle wheel and hold it in front of you by each end of the axle, spin it forwards or backwards then try to turn the axle to the left or right.
The precession force is huge considering the inertia of a tiny bicycle wheel/tyre, one direction of spin and the wheel "falls " into the turn direction
Spinning the opposite way its all but impossible to get the axle to rotate left or right by hand at all.
The amount of resisting force involved is simply staggering when you try this.

[Flettner]

Good article Breezy, thank you.

[Drew]

The direction of crank spin has a huge influence on the bikes stability on corner entry and exit.
This is the precession effect,and we tried it experimentally when arguing about the crank spin of the BSL500 design.
Get a bicycle wheel and hold it in front of you by each end of the axle, spin it forwards or backwards then try to turn the axle to the left or right.
The precession force is huge considering the inertia of a tiny bicycle wheel/tyre, one direction of spin and the wheel "falls " into the turn direction
Spinning the opposite way its all but impossible to get the axle to rotate left or right by hand at all.
The amount of resisting force involved is simply staggering when you try this.
Try the same experiment with two wheels, one in front of each other. Spin them in opposite directions and see what if anything changes.

[wobbly]

Fine idea, but even my wheelchair arms would struggle to hang onto a 4 cylinder crank spinning at 12,000 rpm.
In your two wheel experiment, the resultant precession effect is dependent upon the relative magnitude of the opposing two forces, and they for sure are nowhere near equal
when turning a ridden motorcycle.

[F5 Dave]

So what if you removed the jackshaft and reversed the bike into the corner with the now contra contra rotation of the crank to the driven front wheel offset by the now rather sharpish steering? We'll knock one up. Drew can be first to test ride it.:yes:

[Grumph]

So what if you removed the jackshaft and reversed the bike into the corner with the now contra contra rotation of the crank to the driven front wheel offset by the now rather sharpish steering? We'll knock one up. Drew can be first to test ride it.:yes:

Been done - anyone else remember "backwardgate" as written up in Cycle mag ?
I'm sure Husa will find it - but it's better put in the chassis thread I'd think.

[ken seeber]

Here's an easy way to add on some hp. Not too sure though if it might reduce the expansion chamber efficiency so the nett result in no gain. However, the principle could be used elsewhere.

Wonder how it fits into various bike and karting rules.


http://newatlas.com/drum-charger-cheap-motorcycle-turbo/46648/

[Flettner]

Here's an easy way to add on some hp. Not too sure though if it might reduce the expansion chamber efficiency so the nett result in no gain. However, the principle could be used elsewhere.

Wonder how it fits into various bike and karting rules.


http://newatlas.com/drum-charger-cheap-motorcycle-turbo/46648/

You know, I,ve often wondered if the end of the chamber was super imposed into the crankcase, with a membrane the same could be achived, a pules varried crank case volume.

[jamathi]

Here's an easy way to add on some hp. Not too sure though if it might reduce the expansion chamber efficiency so the nett result in no gain. However, the principle could be used elsewhere.

Wonder how it fits into various bike and karting rules.


http://newatlas.com/drum-charger-cheap-motorcycle-turbo/46648/

There is also my Italian friend NICOLA BRAGAGNOLO making turbo kits for most 300cc bikes.
He uses a real turbo and intercooler.
Very well made!

[husaberg]

"There’s very little all the factories agree on, but engine rotation is one of them After sunshine, rain and fresh air, my favourite natural phenomenon is gyroscopic effect. This is because we wouldn’t be able to ride motorcycles without it. If you don’t believe me, try this next time you’re out riding: when you stop at a traffic light, don’t put your feet down. (And don’t send me the bill.) A motorcycle’s spinning wheels create gyroscopic effect that keeps the machine going straight. The more speed, the more gyro and the more stability. This is all good, unless you are racing. Most racers don’t give a hoot about straight-line stability: they’re happy to hold on like gorillas on the straights, just so long as the bike will turn left or right in the blink of an eye. And this is why all premier-class Grand Prix manufacturers – possibly for the first time in history – now run their engines backwards. It may also explain why Marc Márquez’s COTA and Argentina victories were so huge – bigger than any dry-track wins from last year. When an engine runs forward (like most streetbikes) its crankshaft rotates the same way as the wheels, thus adding to the gyro effect, which makes it more difficult to turn into a corner or change direction. The obvious way to reduce gyro effect is to reverse the direction of engine rotation, so the reverse-rotating crank reduces the total gyro effect created by the fast-spinning wheels. The beneficial effects on the dynamics of a motorcycle are significant: 2the bike will turn quicker and change direction faster; a huge consideration in modern racing when most racetracks are very tight and twisty. A reverse-rotating engine also reduces wheelies, because the crank’s torque reaction pushes the front wheel down during acceleration, rather than lifting it (although this is less important than in the days of two-strokes, when crankshaft inertia was greater.) However, nothing is for free in racing. If you run the engine backwards the engine needs an extra jackshaft to keep the rear wheel turning the right way. That shaft absorbs a significant amount of horsepower, as well as increasing engine weight and dimensions. In theory, a reverse-rotating crank also increases understeer in corners, making the bike run wide on the exit, which can prevent the rider from getting on the throttle. But presumably all these costs are worthwhile because this year Honda reversed the engine rotation of their RC213V, the first time they’ve run an engine backwards since the days of the 500s. The last time Honda went backwards was in 1987. The first NSR500, born in 1984, was a real handful, partly because its V4 two-stroke engine ran forwards. The torque reaction from the forward-rotating crankshaft lifted the front during acceleration, causing plenty of problems for riders who spent too much time fighting wheelies instead of thinking about the next corner. The NSR ran backwards from 1987 and won eight of the last 13 500cc titles."

A bit off topic and random but...:bleh::cold:
All true but the 3 cylinder NS500 ran backwards as well.
I should note however, when the Screamer was reintroduced in the later 90's they kept the Balance shaft as Doohan said it steered better with it in place, that balance shaft of course ran forward.
Nearly All the other GP500's other thean the swiss auto had twin contra rotating cranks

The direction of crank spin has a huge influence on the bikes stability on corner entry and exit.
This is the precession effect,and we tried it experimentally when arguing about the crank spin of the BSL500 design.
Get a bicycle wheel and hold it in front of you by each end of the axle, spin it forwards or backwards then try to turn the axle to the left or right.
The precession force is huge considering the inertia of a tiny bicycle wheel/tyre, one direction of spin and the wheel "falls " into the turn direction
Spinning the opposite way its all but impossible to get the axle to rotate left or right by hand at all.
The amount of resisting force involved is simply staggering when you try this.

The Velo Roarer had twin cotra rotating crankshafts mounted accross the frame with a direct shaft drive it is said to have steered beatifully.
326536326535326534
The MotoCzysz was a bike design that tried to minismise the gyro effect.
326537
http://motoczysz.com/motorcycles/c1_prototype
Regardsless of crank rotation the biggest conributer to the gyro effect on a bike is as far as i am aware the wheels.
All the honda CR125,250,500 shared very similar fame specs, the smaller cranked turn far better due to it small crankshaft the actually CR500 willfully resists any changes in direction.