I have a Mintor 22 as well and it seemed to be losing compression. So I got a contact for Mintor through Chief aircraft where I bought it and Mintor finally sent me a new piston and ring. When I installed it I found that the hole in the piston for the pushrod pin was too large. So I put it back together anyway and turned it by hand and could hear a rattle. So I am not sure what to do now. It took almost 6 months to finally get Mintor to send me the part and it was the wrong one. Should I just put the old piston back in with the new ring?