I made a nice stirling engine from here
I have to add, it need 4 ball bearings 692ZZ (2mmx6mmx3mm) and 2 683ZZ (3mmx7mmx3mm) .Photos show only 2 692 and 2 683.
Assembly is very easy and does not has any difficulty
Maybe with more heat , it run a little faster .What???? You don’t think so?