.020 V-Twin

That one will pressurize the crankcase, like the horizontally opposed ones won't

That one is really well done, seems a shame to do all that work and then use pliers on the cylinders

I nearly owned one.
This time last year while I was in Canada in fact actually in this town in this hotel to be exact.
There were 2 engines I was interested in one of these and a rare "Tigre wasp" micro diesel from Italy.
I had to chose one to bid on, I chose the wasp it ended 10 mins after the twin.
I saw the twin end for around 250 then wet to place my 300 bid on te wasp when the hotel
Wifi burped.
I won neither

Another non-runner...

The topic is well covered in the .049 multicylinder thread. Two-stroke multicylinder engines have to fire simultaneously or have a compressor to keep up the pressure in a common crankcase.

A "V" may run as the pistons are in different positions...

RknRusty wrote:That one will pressurize the crankcase, like the horizontally opposed ones won't

Surfer_kris wrote:Another non-runner...

The topic is well covered in the .049 multicylinder thread. Two-stroke multicylinder engines have to fire simultaneously or have a compressor to keep up the pressure in a common crankcase.

I looked at it for a couple of minutes before making that bold declaration. The rising piston does relieve pressure caused by the descending piston, but depending on the angle there should be some crankcase pressure.
I'll try to step through it again.
Do Harleys have separate crankcase chambers?

"This 2 cylinder twin engine was a one time production by Cox not a homemade/custom build, so this is a very limited very rare engine."

I sure hope the buyer got some documentation with this. Somehow I think Cox would've done more (even for a prototype) than just hog out the crankcase out of a piece of bar stock and grind down the rod big ends to fit side by side on a PeeWee crank...

It isn't a prototype coxjust did a few experimental multi cylinders for fun I think I doubt they ever had plans to produce them.

On a two-stroke engine the the cylinders have to work in phase (i.e. fire simultaneously) or they will have problems with lack of crankcase pressure (in a common crank-case design).

So if the cylinders have a common crank-pin they have to be inline. Or you can have to different crankpins and then still have the cylinders fire simultaneously.

The timing on engines with a timed intake will usually have the intake open for about 170-180 degrees (see AP wasp timing below as an example). On a reed engine this timing is taken care of automatically by the reed valve, supposedly giving similar timings. But you can not have a second cylinder which is offset by a full 90 degrees, as in the v-twin above, as one cylinder would be on its way down while the other is already going up. It may sort-off "fire and run", but the power will certainly be well down compared to simply twice that of the single cylinder engine.

Good diagram Kris!

You're quite right Kris, I agree there is no way to develop any substantial power even if it does crank and run.

Here is a very short video of one .098 i did earlier:
https://youtu.be/QQx9MouMODc

It does suck fuel, we could see it in the fuel line, but there was no tank installed. This video was taken at my work and we did not even had glowclips as it was more or less a question about "you do not dare to start that one..." from my colleages.
I still have the engine and i have now mounted a 5cc fueltank on it but have not run it since, hmmmm........
It will NEVER produce the same effect as two .049's!!

Regards
Thomas

RknRusty wrote:
Do Harleys have separate crankcase chambers?

Aren't harleys, like, 4 stroke?

Harleys are four-stroke AND don't rely on the crankcase to pressurize the air.

The screaming jimmies (two stroke diesels) have a simular problem with air intake. That's why they use a blower to move the intake air around

dirk gently wrote:

RknRusty wrote:
Do Harleys have separate crankcase chambers?

Aren't harleys, like, 4 stroke?

Duh.. somebody must've hacked my account and posted that.