Oddball engines and prototypes

[Frits Overmars]

If I keep it piston ported, is there any reason I can't put a transfer port or two above the inlet port?

No theoretical objection. You'll just have to find the space for it.

Creating reasonable directions will be based on some good stuff I read somewhere about Pizza slices, or something.

Cooling the lump shouldn't be my biggest problem, Lots of airflow available.

Airflow won't be the problem; heat flow from the cylinder bore to the outer ends of the cooling fins will be, and there is not a great deal you can do about that.
Cast-iron will be cast-iron, you know.

20HP at the rear wheel will be ideal

Now we are running into conflicting desires. With maximum power at 9500 rpm, you not only need over 100 mm of total transfer port width, you'll also need a corresponding amount of blowdown angle.area. With 190° exhaust timing that just isn't achievable. We're dealing with a short-stroke engine here, remember?
You'll need a main exhaust port 194° high and 45 mm wide and two auxiliary ports, each 192° high and 20 mm wide. And I bet there isn't enough cast-iron around
and the cylinder studs would be in the way. But if you manage to realize the above, and if you don't totally mess things up, you'll have more than 30 hp at the wheel.
If you're serious about the 20 hp, why don't you drop the 9500 rpm to maybe 7000 rpm? Then you can use milder port timings and get a more forgiving engine character.

[Grumph]

Airflow won't be the problem; heat flow from the cylinder bore to the outer ends of the cooling fins will be, and there is not a great deal you can do about that.
Cast-iron will be cast-iron, you know.
If you're serious about the 20 hp, why don't you drop the 9500 rpm to maybe 7000 rpm? Then you can use milder port timings and get a more forgiving engine character.

This approach works - my 197 Villiers is tuned for peak power at 8000 - but is very torquey from around 6000. Light bike pulling a high gear.
Probably makes a little more than 20HP (optimistic brag...)
The drawback to this is chamber length. the one on the Villiers goes down the left then has a short section across in front of the rear tyre before going up the right side.
Heat flow in the fins at least has only a short trip to the tips (cough)....I'm going to give the bike one more go but on alky this time before possibly doing a watercooled conversion.

[WilDun]

.
And...just to prove that an old mower engine is not a hijack of the rotary discussion.....
Cheers, Daryl.

Is it cast iron? if it's cast iron its good - cast iron is the best material - ie for playing around with anyway.

[WilDun]

Going back to HCCI, (and I know it's a silly question) - how well would the side valve engine work with HCCI? - (or with the use of hydrogen fuel!),seeing that combustion chamber shape is not so important as it was.
Of course there is the uneven heating to consider (but that doesn't appear to be a problem in a modern two stroke).
Just a thought - a SV engine looks quite compact and tidy compared to a modern four stroke, with a head as big as the rest of it!

DARYL, this thread was made for hijackers, that "other" thread is tough going for hijackers!

[eldog]

Maybe what he meant was they are better at constant sustained high rpm than the competition is.
Their balance is superior which help as does their lack of poppet valves.

or maybe he was refering to the competition carbon apex seals used until mazda devloped the ceramic seals..
these initial carbon apex seals were only effective at high rpm.

I guess I will never know.

most likely from balance, he lectured us in thermodynamics mostly air con related stuff, but occasionally got ahead of himself and diverted when asked random questions from the inmates

he also researched engines and combustion etc, followed hydrogen and electric development.

cool dude, knew his stuff.

[husaberg]

Thanks for the input Frits. 130 degree of transfer was exactly my plan (& say 190 Ext & 166 inlet)

100mm of width should be doable. Efficient ducts to feed them will be the tricky part.

If I keep it piston ported, is there any reason I can't put a transfer port or two above the inlet port?

As I don't have direct access to the crankcase, except by tapping into the main transfer,
I am thinking of creating transfer 'holding chambers' outside the cylinder and feeding the extra ports from there.

Creating reasonable directions will be based on some good stuff I read somewhere about Pizza slices, or something.
Actually optimising and balancing the flow without a squillian hours of Sim & Dyno, is unlikely to occur.
I'll just try to make it look a bit like something that is known to work rather well.

Cooling the lump shouldn't be my biggest problem, Lots of airflow available.
I can even add water vapour to the air, if required and using Methanol fuel is another option.

20HP at the rear wheel will be ideal, with enough torque to steadily climb back from 38 & 27% rev drops in the lower gears.
I am also considering a CVT or go kart clutch between the engine & gearbox to help cope with this, despite the power cost.

I'm putting some pictures together, to post soon.

cheers, Daryl. PS Not many would go there, in fact None have....that why I'll do it!

http://www.vintagekart.4t.com/catalog_3.html

[Flettner]

.
And...just to prove that an old mower engine is not a hijack of the rotary discussion.....

Attachment 331543

Attachment 331544

Attachment 331545

Discussion & more pics here: https://www.outdoorking.com/forum/ub...t&Number=42597

Cheers, Daryl.

I had one of those. Had the hacksaw resting on it ready to modify it into a super charger for my Honda 100 bucket racer, back in the day. I couldn't bring myself to cut it up as I figured they were quite rare, so ended up giving it to an engine collector. Ended up cutting up a roots supercharger and thinning it down to 25mm to get the required pumping volume. I'd seen plenty of these about.

[Pursang]

Now we are running into conflicting desires. With maximum power at 9500 rpm, you not only need over 200 mm of total transfer port width, you'll also need a corresponding amount of blowdown angle.area. With 190° exhaust timing that just isn't achievable. We're dealing with a short-stroke engine here, remember?
You'll need a main exhaust port 194° high and 45 mm wide and two auxiliary ports, each 192° high and 20 mm wide. And I bet there isn't enough cast-iron around and the cylinder studs would be in the way.
But if you manage to realize the above, and if you don't totally mess things up, you'll have more than 30 hp at the wheel.
If you're serious about the 20 hp, why don't you drop the 9500 rpm to maybe 7000 rpm? Then you can use milder port timings and get a more forgiving engine character.

Rats, I had up to 120mm,...NO way to get 200. That's OK, I'm still at the Drawing (circuit) Board.
Here is the space I have to work with, (with some wishful thinking).

45 years with a hot-rodded Bultaco (195/135/172) I've forgotten what forgiving means. (I do know what 'loaded-up" means).

Cylinder studs should/would/could be a problem, but I can revert to the original setup with short studs into the case to hold the cylinder down. This gives access & room for the A & C transfers and the exhaust auxiliaries.
Bolt the head down through the top 3. External structural bracing if required.

This approach works - my 197 Villiers is tuned for peak power at 8000 - but is very torquey from around 6000. Light bike pulling a high gear.
Probably makes a little more than 20HP (optimistic brag...)
The drawback to this is chamber length. the one on the Villiers goes down the left then has a short section across in front of the rear tyre before going up the right side.
Heat flow in the fins at least has only a short trip to the tips (cough)....I'm going to give the bike one more go but on alky this time before possibly doing a watercooled conversion.

Pipe length won't be an issue for me, in this application.
I had a friend with a Villiers 197 in a HJH Scrambler, hard to fit a long & fat(ish) pipe with 50's period Style.
Megaphones were more the fashion, back then.

Is it cast iron? if it's cast iron its good - cast iron is the best material - ie for playing around with anyway.

Aaaargh Iron! Dimensionaly pretty stable, 'til it melts?
Almost self lubricating. No thermal barrier at a material change line.
Boring & honing & clearancing to Any size, At home, At will, eh Wil?
Adding and removing bits, repair a score with a piston ring and a Dillon torch! Lots to love.

So here is a 'Phantom', paint shopped, pic of the relevant model 160 engine.
Much nicer ones in the link by Husaberg.



The bump for the main (only) transfer is clearly visible. I'd rather not modify the alloy case.
As I see it I could:

a) Bore into the bump, enlarge access and create a chamber to feed 3 pipe ducts to the A, C & D ports.

b) Similar to a) but remove (mill out) fin #6, cut the new ports and weld in a cover plate between fins #5 & #7.
Sort of a circumferential transfer set up.

c) Go the reed option, create a chamber behind the reed block and feed the ports from there.

d) Fit a blower to overcome any flow & distribution issues. Probably need to discuss sizing options with Flettner.

Undoubtedly, the best option is one I haven't considered, yet.

Sincere thanks, for the advice and comments so far.

Cheers, Daryl.

[Frits Overmars]

Rats, I had up to 120mm... NO way to get 200.

No worries Daryl, those 200mm were a typo. It should have read 100 mm. I have corrected the concerned post.

[ken seeber]

Daryl,
Here’s a pic of what someone over your way is doing. Obviously, with the bolt on transfer passages, it is based on a 125 & is still a 125, but I think the 160 had cast-in “open trench” transfer passages, so this may be more difficult than just bolting on.

[Pursang]

Yes Ken, the 160 has the cast trench transfer ducts.

The plastic hose on the 125 transfer cover has got me thinking.
I guess its the impulse line for the pumper carby......but if I found some larger tube, that could handle the heat of a red-hot iron barrel, I could make nice smooth extra ducts without the hassle of putting compound curves in S/S or Copper or any other metal.

Cheers, Daryl.

[Pursang]

Lasts a fair while in the frying pan. Min bend radius for 16mm is 165mm, could work.

found here: http://www.flexicraft.com/industrial_hose

cheers, Daryl.

[Pursang]

It helps if you know what to Google for!

19mm Silicon Hose used by Turbo enthusiasts (& young, noisy "Doof Doof" import driving, wankers).

[Frits Overmars]

Lasts a fair while in the frying pan. Min bend radius for 16mm is 165mm, could work. found here: http://www.flexicraft.com/industrial_hose

Aprilia transfer duct inner radius is 16 mm. What's more, with insufficient blowdown (could already happen if you rev it a bit higher than intended) exhaust gases will enter the tube and the PTFE will give off very nasty fumes.

[Pursang]

Aprilia transfer duct inner radius is 16 mm. What's more, with insufficient blowdown (could already happen if you rev it a bit higher than intended) exhaust gases will enter the tube and the PTFE will give off very nasty fumes.

The ducts Will be longer than ideal, but might add some additional case volume.

Extended over-rev is unlikely once in top gear, assuming gearing is correct.

Won't be anyone behind me to breathe the fumes.

cheers Daryl