Algodoo

Indeed, there's a lot you can do to improve it.
first of all, the pistons should move far less on the cylinder, and you should find a way to delete the ball ONLY when the piston has reached bottom dead center (when it's all the way down) or 15º before that.
Why did you use legacyMode 0 axles for the rods? You'll see that if you drag the flywheel very slowly and you leave it spawning balls, the hinge will stretch a bit. you're losing a lot of energy there!
Also, it may sound strange, but restitution is crap on spawn engines. Use restitution 0 and friction 0 on all parts.
And if you want a lot of power, the inverted V shape upon the engine has to be a lot more closed than that, so that it impulses the ball downwards. Try leaving 30º between them (right now it seems to have 150º)
Remember to always use legacyMode1 on axles unless you need very high speed

@The Linkage - Thanks alot. Your tips will definitely help in the coming engines I'm going to build.

Your engine produces about 7 to 8 kW. After tweaking it a little I pushed it up to 40 kW although it was a little unstable.

Great work anyway!

And by tweaking I meant messing with the spawning script only.

Thanks Cathier