22 wrist pin mark on cylinder wall.

My 22 had aluminum plugs that fit in the side of the piston. I don't remember the piston having grooves in it for the snap rings. Jeremy

I seem to recall reading recently in a 1930's Service Magazine, about the change from the aluminum plugs for wrist pin retention, to snap rings.
I'll see if I can find it again. Long grooves in a bore are bad news, they increase oil consumption and blowby by a considerable amount.

There is a clip on YouTube showing the piston been machined to take the snap ring instead of the plug,piston is out of the engine.
Andy 😊
http://uk.youtube.com/watch?v=H4X-DnIbMMs

This is not a good thing, how deep has it dug in? If there was originally an aluminum plug, it was obviously left out when it was last down. Most of them used a snap ring, some were round spring wire and then there was also a normal type snap ring. I have seen them come out before (usually due to incorrect installation) and it wreeks havoc on the cylinder. On a modern snap ring you will have a sharp side and a rounded side, put the sharp side facing out and on all types place the gap pointing up.
Mike