Modular compressed air engine. v twin, v8

Here is my 15.1mm bore x 8mm stroke air engine, It has no moving parts other than the piston and crank, it is very simple to build and is modular, the file here will proint one V twin, i will upload subsequent files to enable the v8, inline 5 and v10 soon. It can run at very low pressure once well run in, it can run with you blowing down the inlet and at 5 bar it absolutely screams.

I will add better instructions at some point but its pretty simple and some knowledge is assumed as... well you're obviously interested in air engines.

Hardware required:

8x14x4 ball bearings (you may even be able to download printable ones elsewhere.)

5/32" (3.968mm) ball bearing - I'm certain it would work on 4mm if that's what you have

Everything presses and slides together, ideally you should put a tiny bit of superglue on the cylinders to hold tje cylinders and crankpin in place. Deburring the piston will make run in far easier.

https://youtu.be/Kkrgax0hOLA?si=-eVpmZ5egzk1F2zy