Summary

This is the second time I have designed and printed a working air engine. I am very pleased with this version and I hope to develop it further into a functioning car. The alignment issues I experienced with the previous design have now been resolved.
I used 100% fill for the cylinder.
You will need drill bits. 2mm and 4mm.
PLA 1.75mm
you can watch it here Air Engine #2 Design Part 1
https://youtu.be/zWuH6Cx_52M