This small engine runs absolutely great for me, this can be powered by a regular vacuum(Tip: make sure its not a weak vacuum). After assembling the engine, I recommend supergluing the top and bottom piece, be careful not to get in on the crankshaft itself. This should spin smoothly, and be able to make a few rotations easily. I recommend printing with 30% plus infill and 1mm thick walls. I am open to suggestion, please and thank you! 

Check out my V3 version now!

[https://makerworld.com/en/models/2559684-small-vacuum-air-powered-engine-v3-throttle](https://makerworld.com/en/models/2559684-small-vacuum-air-powered-engine-v3-throttle)