New oil rings too tight...what to do?

[67Dad]

Rebuilding a 350 SBC. Original bore size. Honed and got new rings. Oil ring spacers have "accordian" pattern 90 degrees different from originals. Top/Bottom Oil Rings will not compress enough to put into cylinder.

What to do? Sizes are correct as best as we can tell, but the spacer ring stops will not allow oil rings to compress. Note that "gap" in spacer is smaller than original...can it be snipped off to make the gap wider???

Thanks in advance!

Mark

[hugger6933]

I would'nt snip them but filing them down is an acceptable practice used often to gain the proper ring gap. Jim

[67Dad]

Old ones have the accordion pattern radially, new ones have it axially. Old oil spacers have an uncompressed gap of around .325...new ones about 1/3 of that. (It is a BIG difference...not just a little filing). My son and I can't find any specs at all on the oil ring itself...what the gap is supposed to be or how to best measure it. I'll try to post a picture if I can figure out how.

Another possibility...use the new rings with the old spacers???

Thanks.

Mark
PS: My son found on another board a similar problem...MAY have something to do with Chevy switching oil ring groove depths...we might have "shallow" groove pistons where the oil ring spacers go. Arghhhh!

[oldgold70c10]

Depending on what year the engine is (or where the pistons came from), it may have shallow oil ring groove pistons & you are trying to install regular groove oil rings. Easiest way to tell is compare the oil grooves with the compression ring grooves. If the oil groove isn't as deep, you've got shallow oil ring pistons. Seems like engines in the late 80's and 90's had these.

[oldgold70c10]

Sorry, just saw your last post. You're already onto the deep/shallow groove thing.

[67Dad]

Pretty convinced its the deep/shallow oil ring piston problem. http://www.nastyz28.com/forum/showth...=183170&page=2 has some good pictures.

Thanks.

Mark

[swamp rat]

Be sure you take each ring ( all of them, compression, mid, oil scrapers) and put it in the bore and squair it up with a piston for the cylendar its going to be run in and check the ring end gap before you try and install the rings on the piston, if the end gap is too small you run the risk of seazing up the engine. the instructions should give you the end gap requirement.

[67Dad]

Problem solved with a set of rings for "shallow oil ring grooves". Everything else went smoothly...engine back together. (Still need starter, carb, fuel pump, etc...but making good progress!)

Thanks for the help.

Mark