Total seal 2nd rings

[Jim Comet]

Has anyone seen this? On 6 of the 8 pistons the cast second ring was broken in multiple spots. This is the worst with some sections missing. Most were broken in 2 or 3 places but held in place by the 2nd piece of the 2 piece second ring. Don't think I will use the 2 piece rings again. The cylinders actually look fine as do the pistons. I'll check the 2nd ring groove carefully when installing new rings. I wonder if this was costing me a little power. Jim

[machoneman]

That looks like a classic case of ring end-butting. What was the 2nd rings clearance on assembly?

'Bro James brought to me long ago a fellow's SBC Camaro spitting oil like a Texas gusher. Told the kid to teardown the engine. He did and then showed me broken top and 2nd rings, in pieces, just like yours!

Never checked ring end gaps and said he had great difficulty with installing the pistons on assembly. I think he broke most of the rings when hammering (!) them in. Amazingly, the lands were o.k. and when bro' himself put in new, properly sized rings the engine ran just fine.

[Jim Comet]

I assembled this motor in 96-97 so I don't remember exactly, but .021 jumps to mind. They were file fit and I used Total seals formula and fit each ring to the cylinder it was going in per their spec. The engine didn't smoke but was down a tenth or two from the first few years I ran it. Never used NOS or any power adder and shifted around 6 grand. This is the same motor that had the odd bearing marking on an earlier post. I will check the 2 unbroken rings tonight to see if the ends are polished from rubbing/butting together.  Jim

[jayb]

If the ends of the intact rings do not show evidence of touching, I'd be thinking a detonation issue caused that damage...

[scott foxwell]

If the ends of the intact rings do not show evidence of touching, I'd be thinking a detonation issue caused that damage...

How about radial depth?

[Jim Comet]

Scott, I am not sure what radial depth is or how to measure it. I'm just a small time hobbyist. This motor was a zero deck with flat tops and 58cc chambers so it was running around 12 to 1 compression. I did run it on pump 93 in the street with the timing backed off a couple of times. Otherwise it always got at least a 50 50 mix of race gas. This was probably why I started to get oil leaks and had to wire the dipstick in even though I had a breather on one valve cover and a PCV on the other valve cover. I have to say the motor still felt strong but its a good thing I pulled it apart when I did. Jim

[Barry_R]

Few things.

First is that in my opinion - multi-piece top and second rings are junk.  Marketing gimmicks.
A cast ring is always subject to breakage under extreme duress or over-expansion - the multiple pieces allow more room in the groove for the parts to dance around.  Second rings can fracture upon installation if they are over-expanded or twisted into position.  You might now realize that a crack or cracks have been initiated. 

Detonation will get them too - the top ring and ring grooves should show some signs first if that happened.  Is the top groove looser than you remember - or is the second groove getting kinda tight?

Can you provide a nice clear sideways image of that top ring?  Something looks funky there but it could just be the image.  Judging by the color above and below that top ring it appears to have been sealing.

[machoneman]

Piston top pics too as they should also show effects from detonation.

[Jim Comet]

How is this for a side picture?

[Jim Comet]

Here is a top photo.

[machoneman]

Take a feeler gauge (.001 and up) to see the clearance between the land and the ring. Collapsed ring lands are another sign of detonation, meaning the rings are pinched (won't spin, no gauge will fit) between the lands...although usually the top land collapses well before the 2nd ring's top land. Detonation severe enough to break rings should also show piston top damage. How do they look?

Perhaps your actual timing was far higher than a timing light would show due to inaccurate balancer marks, a slipped outer balancer ring, etc. Also, race gas that's not what it appears to be could be another culprit. No easy way either to test the true octane rating versus the advertised rating. Local racers will know who's selling junk gas btw.   

On edit: tops look ok. Did you use a ring expander for the rings or walk them on?

[scott foxwell]

Is that a gapless second?

[jayb]

Scott, I am not sure what radial depth is or how to measure it. I'm just a small time hobbyist. This motor was a zero deck with flat tops and 58cc chambers so it was running around 12 to 1 compression. I did run it on pump 93 in the street with the timing backed off a couple of times. Otherwise it always got at least a 50 50 mix of race gas. This was probably why I started to get oil leaks and had to wire the dipstick in even though I had a breather on one valve cover and a PCV on the other valve cover. I have to say the motor still felt strong but its a good thing I pulled it apart when I did. Jim

Radial depth would be a good thing to check, I got a set of rings once that were supposed to be back cut and they weren't, so the pistons wouldn't install.  Jim, radial depth is how far into the groove the ring can actually go.  You need the ring groove to be deeper into the piston than the width of the ring, so that the ring is not forced between the back of the ring groove and the bore.  Turn a ring around backwards and push it into the groove; you should be able to see that the edge of the ring is inside the piston surface; if so you have clearance.  If the edge of the ring is flush, or outside of the piston surface, the rings are too wide for the piston groove.

[scott foxwell]

Scott, I am not sure what radial depth is or how to measure it. I'm just a small time hobbyist. This motor was a zero deck with flat tops and 58cc chambers so it was running around 12 to 1 compression. I did run it on pump 93 in the street with the timing backed off a couple of times. Otherwise it always got at least a 50 50 mix of race gas. This was probably why I started to get oil leaks and had to wire the dipstick in even though I had a breather on one valve cover and a PCV on the other valve cover. I have to say the motor still felt strong but its a good thing I pulled it apart when I did. Jim

Sorry Jim...missed this. Like Jay said, radial depth is how deep the groove is in the piston vs the width of the ring. Think of it as the "ID" of the ring when compressed. Jay pretty much covered how to check it.
If there was enough detonation to break the second ring, you'd see evidence of it on the top ring.
I'm going to answer my own question and say it looks like you have gapless second rings. I, personally, would advise against that. I'm not a fan of gapless rings in general, but the second ring is no place for them. It can cause pressure to build up between the top ring and second ring lifting the top ring off it's land. The top ring seals in two places...not just against the cylinder wall, but also against the ring land in the piston. If the ring loses contact with the bottom of the land it can lose cylinder pressure and cause a loss of power. Race engine builders started seeing benefits in thinner and thinner rings and those that liked the gapless rings still wanted that technology but because rings, especially top rings, were getting thinner and thinner, they didn't have the material that could take the heat and still build a gapless top ring so they moved the gapless ring to the second ring where it sees far less heat. Now days we have real good top ring technology and the gapless second is a thing of the past. I guess what I'm getting at is, since you;re going to have to replace the rings, I would not recommend a gapless second. The second ring is not a compression ring and really shouldn't be treated as one. It's an oil scraper and trends these days are to open up the second ring gap even more than the top ring. This allows any pressure ethat gets by the top ring...and there will always be some...a place to escape and not build pressure between the two. Not sure how that plays into what you had happen there, but I just thought I'd throw that out there.

[Jim Comet]

Thanks everyone. I plan on using a standard style ring set when it goes back together. Jim