m_ridzon

Update for anyone who strolls here and is thinking of installing new rings on OEM pistons...
Sealed Power advertises E-971K rings for the application. However, in the fine print, they note that their oil ring expander is for 2.5mm piston gap. But the OEM piston only has 2.0mm gap. Thus, the E971K Sealed Power rings will not fit the OEM piston. Don't ask me how I ran upon this mishap; instead just send me condolences (and/or money) for lost time and return shipping charges to RockAuto. LOL! I'll now be buying genuine OEM rings for my project.

DrLoch

Learning has occurred. Been down that road a lot.

m_ridzon

Update again, for any folks who stroll through here looking for info:
I've bought a brand new set of GM OEM rings. I'm about 99% sure the top compression rings are moly. The GM package doesn't say, nor could I dig up the information anywhere. But, if I look at their end butts under magnifying glass, I'm pretty sure I see the moly inlay.

The top ring face is a "barrel" face, which means the ring can install up or down, either way, and function properly.

The second ring is a Napier cut, which means it only installs one way. It has "top" inscribed in the top side. But if that inscription is indiscernible, it's pretty obvious to tell that the Napier cut on the outer face points down, which helps scrape oil off the liner during the down stroke.

And of course, the bottom oil ring is a no-brainer. It's a standard 3-piece design like many others (one expander sandwiched between two thin rings).

Be sure to gap them properly before installing (I checked mine and they were all in spec right out of the box). And be sure to place the end gaps staggered properly around the circumference.

Cheers!

DrLoch

FYI the factory 1st & 2nd ring end gap is too tight if you've done anything to increase performance. That will break the ring lands, which was common after increasing boost. Just a thought

m_ridzon

Three reasons I'm not concerned about that:

1. I did not replace my liners and pistons. As such, they had a smidge of wear, thus opening the ring gap slightly.
2. The ring gap I measured was on the "high end" of the allowable range.
3. My engine has no performance mod's and will likely stay that way as long as I own it.

But I certainly appreciate you sharing the feedback. It's always good to know these things.

DrLoch

Copy that. Just wanted to pass on information that has bitten others

m_ridzon

Just out of curiosity...how much extra should be 1st & 2nd gaps be opened to facilitate performance increases?

DrLoch

Don't recall the Std ring gap, Take the bore x .0055 or .006 for the top ring. Bore x .0055 -.0057 for the 2nd ring. See where that compares with the factory

Cat Man HHR

DrLoch I have a question.
You say to widen the end gaps when doing performance updates.
My SS has a Trifecta tune that gives me close to 25 lbs of boost vs the stock 14/15. The engine is stock other than the tune.
Where is the threshold to start widening the gap ?

m_ridzon

I was wondering this too because I know of plenty of people who do a quick and easy tune on theirs, but never tear the engine apart to widen the ring gaps.