Lapping piston rings

[Ed Wright]

I still have my stuff for that. When I was running my old C/SM car in the mid '70s I was WD for Manley. Their Pistons were stocked with no top ring groove. 2nd was .043", oil ring was 3/16". I bought them that way.

My ring fixture is/was 4.030" on one end, 3 7/8" +.060". (Had a 292" & 306" engine.) Had a sharp machinist friend that made a fixture to hold the Pistons, and a tool to cut them. After lapping both sides flat while compressed I lapped them to .041". We used .0005" vertical, and .001" back clearance, with .040" vertical gas ports. Had a piece of 3/8" steel plate parralell ground to lap them on, laying in my parts washer, with the pump flooding the paper.

I had one end opened up to 4.070" for my present engine. Not as easy to see on these shiney .028" Total Seal rings as the black .043" rings, but they appear to be flat. Layout ink also comes off first swipe on 400 wet or dry paper.