Hey everyone. I am trying to put my LS6 back together after it ate a valve spring in January. I had the block cleaned an honed. My current step was to get the piston rings gapped. I bought some Hastings as they are made in the USA. Anyways my top ring gap is not good. For my top ring my gaps are all close with them being between 0.026-0.027. However by the book it looks like I need 0.017-.021. This is confirmed with a few other ring gap calculators. Car is a street car. Its never going to see boost or nitrous. Anyways out of curiosity as I was wondering if the machine shop had taken to much off the wall. So I slapped the second ring in and well I have good news there. Everything was 0.016-0.017. A little tight, but I can open that up to where I want it. Buddy across town does have a cylinder gauge that would check the diameter. So I am wondering if this is a ring issue. If so those who have rebuilt their cars which rings did you use.

This brings me to the next step. Should I order another brand of rings. I can get some Mahle from work on Tuesday. Hastings offers a .005 overside ring as well. But I have not seen that before. Kind of stumped as the top ring is so lose compared to the bottom. Granted I had two lifters from BTR/Delphi come bad out of the box today so where are backed up a till next weekend. Cant get quality parts anymore.

 

If you bought what should be pre-gapped rings, you need to check bores and pistons — although if the second compression have good gaps that does seem questionable. Have you contacted the manufacturer to see if they were made with different gaps on purpose? Do verify piston to bore clearance is in tolerance.
There’s a really handy axiom for this:
If your end gaps are too large, you will always know it. But if the gaps are too small, everyone will know it.

 

So it looks like there are pre gapped rings. At least Summit says the are not file to fit. I am going to work on checking piston to wall clearance. I should pop one of the old rings off and check its gap. Piston looks tight in the bore as I am using one to push the rings flat to check gaps.

 

Well this is confusing. Got some Mahle Piston rings today. Top rings are ok running from .019-.024 gap. The second rings are way out of spec at .028-.032. I took the stock piston ring off #6 and and shoved them in the hole. Top ring was .018 and the lower was .028. So the lower ring was out of spec. But this shows that the hone job did not take off to much. Might send both sets back and call Total Seal and see what options they have.

 

Before I got any more rings I would ask the ring manufacturer tech support. There has to be some explanation. Good luck

 

Have you considered gapless ring sets?

 

Called Hastings and got no help from them other than saying send them back. Mahle I got zero answers from them. Decided to order some Summit branded rings, opened them today.....99% sure they are Hastings as the box and bags look the same as my other Hastings box. So those are probably going back as well.

I was looking at Total Seal rings. However this rebuild is already way over budget and it should not take a $503 set of rings to solve a simple LS rebuild. Going to really look around this weekend and get the bore gauge to check these cylinders out. Hopefully they are still round and in spec.

 

Ring gap depends on location on the piston and type of engine use, induction pressure.
https://wossnerpistons.com/pages/4-c...gap-calculator

 

From what I can find online, the top ring has tighter gap requirements than the second, and wider tolerance on the oil control rings. I admit I don't have a Z06 FSM to check LS6 requirements, so that would be a great place to double check, but from LS1gto.com, the requirements seem to be:
Top ring: 0.009-0.0196 in
Second ring: 0.0173-0.03 in
Oil control: 0.007-0.032 in
Makes me wonder if maybe the ring packages were miss-marked, with the 2cd compression marked as first, and vice versa.

 

From my buddies 02 FSM confirmed the numbers above. Some rings are marked and they were even painted in the Mahle Box. Yeah that could be. But the 1st ring looks the same vs the old one and the 2nd rings have the same angles to them so I am doubting that. Not that it could be wrong. Going to dig into it some more tomorrow. Trying to pick up the bore gauge tomorrow.

 

I'm not an expert on this stuff, just based on my own research, for my first ever ls engine rebuild that I did by myself this past winter I had that engine apart only left the crank in it , I also did a flex hone myself, came out with nice cross hatched walls. Anyway so I went with Mahle 41850CP rings, from Amazon cost was $99 ...so I even bought the rung filer just In case, ended up not using it , the ring gap was perfect to spec like it needed to be. (I checked double checked every cylinder just to make sure ) vette runs strong as a right now just working on getting good tune. So hope that helps good luck

 

Yeah I have a set of the Mahle sitting here. So far they are the best top ring, but the bottoms are on the loose side. But ready to send back $200 in ring sets. Probably going to be what goes into the engine.

 

The Mahle sound fine, run em and don't worry about it. Anything I've read lately says it really doesn't matter that much as long as they don't butt ends. The 19-24 thou rings are fine. What I've read is that the second and top oil ring should be 15-20 thou more so there won't be any pressure below the top ring that would unseat it from the piston. Apparently, that hurts top end power while more gap just doesn't cause any measurable power change or use more oil.

 

Yep at this point the Mahle are going in. I'll file down the lowers a bit and put it together. Now I am just waiting for two lifters to come in so I can debate swapping lifters out as I am having a bad feeling about these Delphi units. So at this rate we might have an engine back together before New Years.