Algodoo

Spawn circles instead of boxes. It'll give you more power. Also quit restitution to ALL the objects including the spawned balls, it will make the engine more stable.
Make the friction of all the objects zero too, and make the pistons and spawned balls MUCH heavier (balls with density 200 or more, and pistons of density 50) and rods too, that increases torque and speed brutally!

Also making frequency higher than 100 Hz is cheating for me, you're making the engine faster by modifying a variable. Try to run this at 100 Hz, staggering the pistons or doing anything else

Thanks for advice, i am making something new