A few weekends ago I began to re***emble my engine for the Suburban. I put the rings on the pistons, went to slide the first one in and it was tight. Bad tight. We pulled ( more like drove) it back out, ran the groove cleaner through it again, reinstalled the rings. Put it in again, and it was still the same. Mic-ed everything, 350 chevrolet: 4" bore, pistons measured right, ring gaps were good. Gave it a week, tried again. Finally, I removed the top ring, made no difference. Removed the second ring, made no difference. Removed the oil ring, re-installed the other two, and it was perfect. I looked atthe oil ring a little closer, and it seemed that it was too deep for the oil ring groove. Grabbed an oil ring from a different set, popped it in and it went in great. Anybody had this problem? I was using Summit brand "stock" rings. The motor is a stock bore 350 "belly ****on" motor.
There are deep groove oil rings and shallow groove oil rings. With corresponding deep and shallow ring grooves in the piston..You appear to have a shallow groove piston and deep groove rings.This combo is very nearly impossible to make work.However a shallow groove ring in a deep groove can be done if you have 3 hands to install the rings.Need more info what year is it and are you doing a re ring or did you also change pistons.Summit didn't make the rings they are probably private branded.You can tell whose rings they are by looking at the oil rings and the instruction sheet in the box,and where the dot is on the second ring. Here is the info that will get you going. Hope this is helpful http://www.hastingsmfg.com/ServiceTips/oil_ring_groove_depths.htm Regards Tig.
It sounds as if the top 2 ring grooves are deep enough, rings have to be slightly below the edge of the piston when pushed in. The oil ring land however may not be machined deep enough. ***emble the oil ring pack and see if it is below the ring land when pushed in.
'62-'85 4" bore with deep groove '86-'95 4" bore with shallow groove (.165") There are also '92-'97 5.7L shallow groove "metric" (VIN "P") 2.0x1.5x4.0 MM Grooves Look at the pad number (in front of p*** side head surface and see what engine you have) along with casting number. And, hope the pistons are original to that motor. Or, it you have the required tools, measure the grooves.
I used to find parts that were boxed wrong at the factory. When that happens nobody knows until the installer can't make it fit.
The top rings should be either 5/64 or 1/16, and you said they were correct. Sounds like the oil rings are wrong. Could be for some other engine. The rear main seal type will tell what gen. 350 you have. No telling who packaged those rings for Summit. I'd be getting some other rings, Sped Pro, Hastings, etc.
1986 / 89 vin k has 5/64" 5/64" and 3/16" ring pac shallow oil groove in piston requires shallow ring.. Pre 89 is same except "not" shallow oil groove in piston requires deep ring. Don't think you have metric rings as the oil rings are 3mm or 4mm oil rings in those sets and that would make the widths wrong,as well the compression ring widths are also metric. I read your post as width on oil ring is good only the depth is wrong.and compression widths are good.This tends to show you have (your new set)early 4" bore rings that were 5/64" 5/64" 3/16" oil for deep groove piston.Your pistons are 5/64" 5/64" 3/16" shallow groove oil ring. That was a problem everything was the same except the depth of oil ring. You need 5/64" 5/64" 3/16" shallow groove oil ring set. Hope this helps Tig.
Yes I just ran into the same problem but with a 454 Gen V motor, I picked up a STD piston from Summit and the Oil ring grove was not as deep as the 1st and 2nd . The tech at summit said that they have had many problems with this India made piston .
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