I'm current working on rebuilding my 3A engine, which was originally rebuilt 15 years ago and sat after only about 5-hours of run-time. The previous rebuild used a new 87mm County piston/liner kit with Grant rings. For this rebuild, I decided to use the same liners/pistons/rings due to there being almost no wear; however, I measured the ring gap to be 0.020" at 3" deep. This is 5-mils over the 15-mil maximum of the 86mm TR4 engine. I believe the 87mm liner bore to be good, as I measured it out at 3.425". So I decided to order new Hastings 86mm 040 rings to see if that would solve the problem, but they only brought the gap in to 0.018". Does anyone know the proper end gap for 87mm pistons? I'm thinking it should be similar to the 86's. Not sure where to go from here if 18-mils is too high. Has anyone else has this issue? These are new parts with almost no wear.
Joel
Joel