Guest Perry Posted May 8, 2002 Share Posted May 8, 2002 Here's the situation, Reringing a 350, I cut the ridge and deglazed in the garage at home, got some summit brand el-cheapo piston rings and am currently reassembling. when I put the first piston in the bore, the fit is so tight that it cannot be moved by hand without a wood mallet. I removed the piston, rechecked ring gaps-all OK, and put the piston in with one ring at a time. found that the oil ring is way tight. measured the width of the outer rings of the 3 piece oil ring and compared to stock old rings and found: stock- .134 new- ~.155 I think this is the problem. Maybe Summit mixed in oversized oil rings with a box of std rings? I wouldn't expect to see that much wear, right? Tonight I'll measure the expander ring to make sure the 20 thousands isn't made up there, but It looked the same to me. Any comments/suggestions? Perry Quote Link to comment Share on other sites More sharing options...
Guest Perry Posted May 8, 2002 Share Posted May 8, 2002 OK, The more I look at this the more I think they sent me the wrong oil control rings, They must be for .040 over. I will send them back tonight, now I have to wait around for parts again. Quote Link to comment Share on other sites More sharing options...
jt1 Posted May 9, 2002 Share Posted May 9, 2002 Try putting one of the thin oil rings without the expander in the bore, then use a piston to square it up and see if the ends overlap. If so, that's your problem. Be sure to check your ring end gap at the tightest place in the bore, usually the bottom of the stroke. Sometimes if the bore has a little taper from wear, they can be ok at the top and too tight at the bottom. Quote Link to comment Share on other sites More sharing options...
Guest Perry Posted May 9, 2002 Share Posted May 9, 2002 In case anyone is interested, here's how the parts measure in the dimension that controls how much ring sticks out the groove when fully compressed into the groove: stock ring= .137 + .025(expander "feet") new ring = .145 + .042 This makes .025 difference in radius. I just realized that summit brand rings don't actually say for Chevy, just 4" bore. I'll just wait to see what they send back. Perry oh yea and the gaps are fine. Quote Link to comment Share on other sites More sharing options...
Guest heinera Posted May 10, 2002 Share Posted May 10, 2002 Just a thought. Did you clean the carbon out of the ring slots on the piston. If you are reusing the old pistons it needs to be done. New rings won't fit all the way in the slot unless its clean. You can use an old broken piston ring to clean out the grooves. Adam Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 12, 2002 Share Posted May 12, 2002 Perry Check and make sure you don't have a late model pisten with low tension oil rings. These rings are thiner than the old style oil rings. Good luck Quote Link to comment Share on other sites More sharing options...
Guest Perry Posted May 14, 2002 Share Posted May 14, 2002 low tension oil rings? That could be the problem. The engine is ~1988 roller cam engine. Thanks for the help, I'll look into it. Perry Quote Link to comment Share on other sites More sharing options...
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