ESE's works engine tuner

[husaberg]

I get that it was unusable A/F mixture (probably mostly oil anyway), but why is it any more of a "pneumatic dampener" than any of the rest of the volume (of the transfers, the volume under the piston, between the crank-wheels, all of it)?? Compared to the total volume, I'd think that whatever the theoretical effect is supposed to be (and what is that, again???), the actual effect of that itty bitty space would be undetectable. Wakaranai, so far.

What Frits refers to re the volumes " hidden " behind bearings, and more relevantly those volumes contained within flywheel balance holes
is that even in my minds eye I can see that there is no way that these volumes can " flow " from these cavities into the transfer duct entry area.
Thus all they do is expand or contract due to the varying pressure ratios experienced within the case - thus are " dampers " contributing nothing but
to increase the overall measured volume.

Smitty What Wob said plus what I guess may have you missed Frits said

. Filling those volumes with plastic bushes gave a measurable improvement.

I see it as to draw these inaccessible volumes requires energy, This energy that could actually be better used drawing in more accessible volumes in the crankcase or transfers.
The fact this is likely repeatedly accelerated and then decelerated without likely being drawn into the transfers actually makes it criminally wasted energy.
These voids are not contributing anything much at all but simply adding inaccessible volume just makes it harder to draw in the more accessible and therefore useful volumes.
Hence why as Frits suggested he has done, When these voids were filled power goes went up.
Its not a question of the actual volume, but the usefully accessible volume.

[seattle smitty]

I read that about the spacers and the "measureable improvement." There's not much point in repeating the argument that the amount of space those spacers occupied is so small as to be irrelevant when measured against the entire volume. Hard to argue with Frits, but also hard not to suspect that something else occurred, unnoticed, during the rebuild to give that measureable improvement. Engines have been known to mysteriously gain, or lose, a little power even during rebuilds in which nothing was modified. Maybe that doesn't ever happen to the masters. Well, whatever.

[F5 Dave]

I've tried to use pistons with short distance from pin to crown, I'd see ideally the pin was in the crown to reduce all that volume there. Obviously this is impracticable.

. . . Sometimes that does happen but the engine doesn't run afterwards.

[wobbly]

Well, as always I have done the repeatable back to back tests.
Rotax 256 with porkchop cranks, and 110 rods.
Replace that with full circle cranks, no cavities and long 118 rods ( before 120 were available off the shelf )so plates needed under the cylinder.
This made the crankcase vol larger, changing it from 1.31, to 1.27.
Of course we have side the issue of less rod angularity, and the larger case, plus increased crank inertia by way of a heap of Mallory to balance the assembly.
But the final result was near on 3 Hp all the way to peak, then a much flattened drop off that gave near 8 Hp at 13,500.
Conclusion, long rod, big case , hight inertia, who cares, the dyno does not lie,when you have repeatable results from adequate weather correction, on an inertia based measuring system, as I do.

[koba]

Husa, it almost seems like you are looking for ways to draw this build out for longer...

[husaberg]

Husa, it almost seems like you are looking for ways to draw this build out for longer...

Actually aiming for a internet record............

[koba]

Actually aiming for a record............

Must spread rep...

[Bert]

Husa, it almost seems like you are looking for ways to draw this build out for longer...

Actually aiming for a record............

Must spread rep...

I can't spread more rep either... Husa just wants to have this ready for his eldest child...

[husaberg]

I can't spread more rep either... Husa just wants to have this ready for his eldest child...

But he's 11 soon, will you accept for my daughter?

[koba]

But he's 11 soon, will you accept for my daughter?

Does that buy you another decade?

[husaberg]

Does that buy you another decade?

I wish.... she's already 7....... perhaps I could adopt a younger one?

okay this is the premise.
I could faf about some more (if thats possible)trying to get a NSR125 to be a 100 but even then I have to hack about the RS125 frame and engine to get it anywhere near fitting.
Its not impossible its been done before.
Or I could just do something more fun.
By me attempting to design something I have figured out so much more about why some engines are actually like they are.
So theses are the things I consider worthy.
it has to have a water cooled case even just cooling the septum's on the later Aprilia's was worth .5 hp so the full cases I am picking are worth plenty more.
The Disk valve is worth 10% extra HP. over a reed.
None of the std legal cases have what I are looking for in either stud spacing or inlet layout or decent gearbox.
The cylinder I have out to be good for nearly 40 (internet) hp. Measured at the usb port
It seems criminal to sling it on a Suzuki RG125.
I want a high mounted balancer or at least an allowance for one.
I want the ignition mounted on the Primary drive side. Out of the way of the Rotary valve
I considered mounting the stator on the balance shaft but I think its not needed it should still be narrower than the frame rails.
Because I am neither talented and I am lazy and cheap I want to use as many std parts as possible.
That's were it gets tricky.
To do a water cooled case it needs a big clutch gear I thought I had that solved with the VT250 tranny but the gear is pretty odd tooth pattern by small Honda stds and its taken a bit of nutting out.
I want a smooth crank I will I guess have to work with what I can find what I wanted to use and have won't work.
I want a square engine around 50.5mm x50.6mm bore and stroke because it has been proved to be the best compromise
I want to use a bloody long rod and I can't see the point in anything bigger than a 20mm crankpin and a 14mm gudgeon for a 100cc
Anyway enough of me blabbering on as in the time I have taken to type this Flettner has made 3 complete engines already from scratch.
The idea is to borrow a shit load of Aprilia tech that Jan and Frits and Wob and others have freely disseminated over the web.

Insert obscure crank pic the result of many misspent hours trolling the net. its obscure yet legal.
Then child like rendering of a backwards mirrored RSW with the balance shaft placed in a more appropriate position


A good place to add the NSR500 crank
I actually never noticed the detail before.

[Sketchy_Racer]

So I've dug out my old MB100 and ran it at kaitoke last weekend. Went really well so I've decided to chuck a little bit of development at it. Starting with a water cooled head.

I've had a quick play around tonight at a insert style head, but am after some constructive criticism of the design.

It's based around the theory of easy to manufacture with only 2 real setups in the mill, and out of 100X100 Solid square or 30mm thick plate.

I've tried to get as much water onto the face of the barrel to try get as much heat out of the barrel as well as focusing on trying to get heat away from the spark plug in the insert but keep more head in the combustion chamber.

There's plenty of space to play with on the spark plug heights for different cylinders (such as mine which has a 2mm positive deck height)

Any way go nuts with pointing out my short comings!

[lodgernz]

better plug cooling than VHM inserts. Gotta be good

[Frits Overmars]

it has to have a water cooled case.... I want the ignition mounted on the primary drive side. Out of the way of the rotary valve

These seem to be the two biggest stumbling blocks on your wish list, Husa. But maybe we can remove both of them.
Water cooled cases are fine, but another option is insulating the inside of the cases, where the mixture comes in contact with the case walls.
My mate Martijn Stehouwer of Emot.nl offers an amazingly effective heat insulation lacquer. He became twice European champion using the stuff.


Next: your ignition. You can put the ignition pick-up on the primary drive side, but you can also go for the Aprilia RSA solution and put it in the outer crankcase wall where it is triggered by a notch in the crankshaft circumference.


Or you can put the ignition opposite the primary drive side anyway: converting a non-rotary engine to the 24/7 inlet system is simpler than converting it to rotary....

[speedpro]

Handy, you've already smashed the ceramic off the plug. Drawn with B8ES size rather than B8HS? A better option I think. Though if going to the trouble I'd probably check if a smaller diameter plug has advantages. I "know someone" who would be interested in a couple. 52mm bore and profiled for a KSI KT100 piston, 50% squish, 0.65 squish clearance, and 14.5:1 compression so about 7.3cc trapped volume.