If I could find a metric ring pack for a 4.375" bore they would be utilized. My go to for a stroker is either a 451" or 511" 400 based engine. Both of those utilize the 1.320 CH piston. On the more serious n20 stuff we use a ductile iron hellfire ring. I want to try this one:
AC 4.375" Hellfire Ductile Iron Ring Set, .017" Dykes top, 1/16" 2nd & 3/16" SS HT oil rings. (set) - Alan Johnson Performance Engineering
I like the idea of gaining meat between the top of the ring and piston crown however the .017" number scares me.
For reference:
1/16" = .0625 = 1.5875mm
.017" = .4318mm
That is a very thin top ring and I would think it would increase the maintenance intervals beyond the hobbyist level.
Maybe we will see some 1.0/1.0/3.0mm packs come out for 4.32 and 4.34" nominal bore size one of these decades.
