In Reply to: Re: Piston rings posted by Bruce(OR) on January 25, 2023 at 02:07:44:
The pistons I have that I removed from two 9N's are both 4-ring units and the top and second compression rings are 3/32" while both oil rings are 5/32", (0.093 and 0.156 respectively. The three ring 8N pistons are 3/32 compression (2 ea.) and one 3/16 oil ring (.187). Entering into this discussion I was planning on using one set of the 9N pistons which looked in almost perfect condition, however when I decided to gather some factual data, brought on by your comments, I found the grooves to be far over spec. 0.115 top, 0.108 second and 0.164 for the bottom oil rings. So now I pulled out my old set of 8N three ring pistons that I removed from that engine about six years ago and looked them over and checked the grooves and they are w/i spec. I took them over to my machine shop and they checked good on diameter and his view was the slight visual scoring wear would not be a problem-so looks like I'll probably use them. New ones from Just 8N's are $45 each (were $20 when I rebuilt the 8N) so adding tax and shipping I'd be well over $200 that may be unnecessary for this engine.
If we had not had this back and forth I might well have spent $130 for a set of rings that would have gone on out of spec pistons before I realized the problem.