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, Jonathan

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.

[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.

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-Part...-Pin::706.html

[husaberg]

http://mora-racing.de/TM-Engine-Part...-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/Siz...%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?