moly rings

[yjmule]

so i decided to use moly rings on my last build. i have been using cast rings since i had a bad experience with the moly rings years ago. i am having a problem with oil blowing back out of my dipstick under hard acceleration. yeah i know i should let them break in before i romp on it....but i have always broke em in like im gonna drive em. never had this problem with any other builds before. i measured ring gaps and all were in spec on assembly. anyone have any problems like this? i hope its just a seating problem.

[unlimitedrubicon]

Who made the ring? How did you seat them? How many miles on them? What gaps are you running?

[yjmule]

sealed power moly rings on sealed power pistons...ring gaps .010....did the usual camshaft break-in with comp cams additive and 15w40 shell rotella (i understand it still has a higher zinc content) pcv system and crankcase vent working fine. no misfiring or weak cylinders.

[yjmule]

prolly 25-35 miles on the rings. lotta folks probably frown on try to twist a fresh engine to hard too early...ive always broke em in like they are gonna be used.

[unlimitedrubicon]

I have never used Sealed Power rings, but .010 seems really tight. Is that the gap they recommend? As a comparison, mine are .018 on top and .022 on the second ring. Those may be too tight causing the rings to butt and then break. Have you ran a leak-down test? If so, what are you getting?

[yjmule]

.010 tight? yep ur right...now that i think about it, that was the tight end recommended by alldata for stock tolerances. mine were actually more like .014-.015 (sorry miller lites fog the memory banks). u reckon i should give it some time?? it doesnt push oil back under regular driving. i dont actually own a leak down gauge and havent used one since school 20 years ago.

[IH 392]

The general rule of thumb for ring end gap on cast pistons is .004" per inch of bore.
Your Molly ring should be damneer seated by the time your cam break in is done, if they aren't the cylinder wall finish is to coarse, witch in turn may grind the molly right off of the ring face.