Jon1212
Riff Raff Fart Knocker from other Forum's.
Jon, was this ever resolved??
Was the cylinder out of round or tapered from top to bottom or both?
Did you use emory cloth or scotchbrite on the piston skirt to smooth it back out and try it again?
Did you file down the rough edges where the chips occurred?
I think the chips/flaking caused the scratches you see......
Poor manufacturing tolerances or too much silicon in the mix of the aluminum made it too brittle and then someone didn't deburr it well enough after final machining????
If I refer to my knowledge of pistons, I have much more background in Automotive pistons, and I have even seen some of those cause the same problems because of the same poor manufacturing/ deburring...
I have a friend that has all of the tooling required in making a determination as to what happened, working on it.
I do know that upon disassembly, by myself, I could see metallic flakes in the bottom of the case.
Hopefully @TermiteBuffet will have an answer fairly soon.