Very strange behavior in one of my stirling engines

[Carlos_A_M]

So... I am currently making a stirling engine, my biggest one so far. As usual, usually I test these engines before connecting anything to make sure all is working, that there is not too much friction, the displacer is not too big or small, there are no significant air leaks, etc. However for this engine once I connect the displacer to the crankshaft the engine simply appears to not work at all. Left alone if I move the displacer manually it generates plenty of torque, enough to nearly instantly start spinning the flywheel, but the instant I connect the displacer it just stops working. I have never encountered this problem before, I tried adding weight to the flywheel, different power strokes, different piston designs, spinning it both ways, etc. But it simply refuses to work. The crank angle is 90 degrees

Video: https://youtu.be/mGOpYQSsdr8

Please, if someone has any idea as to what it could be, please help me!

[Tom Booth]

Your video clip is too brief to see much but from what I can see your crank angle is wrong.

Your piston is already at a 90° angle in relation to the displacer so the additional 90° offset on the crank makes a 180° offset so your piston is in a compression stroke while the displacer is pushing the air to the hot end causing the gas to expand.

Basically you have a sort of alpha type engine design with a gamma type crank.

[Carlos_A_M]

You know what's the worst part. I literally did this on my last engine, which had the 180 angle but it completely flew over my head on this one. I knew it had to be something really dumb but not THIS dumb lmao.

Anyway, thank you so, much!