Gapless Top Rings

[rebelrouser]

I don't have the dyno access to prove any numbers, but I use a leak gauge religiously which I know isn't a perfect tool, but its the best tool I have to check ring seal, and the gapless top ring with a naiper second is the best ring combo I have used. I do have a cylinder blow by gauge I use as well and at leash at idle and reving with no load, it likes the gapless rings as well. I used gapless rings on the second groove one time on my race engine, it did not run as fast, and when I tore it down, it was wearing a ring groove in the cylinder from the second ring, never used them again on my mopar. I have pulled several small and big block chevy's apart for customers that had second ring gapless on them and did not see the same issues. I did not however use them on refresh. It just don't make sense to me to capture the blowby between the top and second ring. Which is what happens if the gapless second ring is working the way they say it should.

[CGT]

I have used them 4 or 5 times, never a before and after thing, I've had no troubles. Worked well in last years EMC engine. I'm still just not completely sold on them, seemingly adding unnecessary complexity. I am contemplating them for my special needs project mostly due to the lower rpm range(time for leakage) but just not sure which way to go. Also, I get great deals on JE rings etc, not so much on Total Seal...so there is that. Thanks for the contributions. I may just flip a coin


https://www.speed-talk.com/forum/viewtopic.ph ... ds#p719642

[steve316]

I have used them and always had zero leak down. but regular moly filled barrow faced rings were quicker even with 2 to 4 percent leak down. I have to say that was in the late 1990's.

[ptuomov]

It so happens that the engine that I'm primarily interested in has a big, big problem of way too much oil being sprayed on the bore walls. To remedy this, one of the most thoughtful people who's ever been involved in working with this particular engine designed a ring pack that has a second gapless ring. This wasn't a fully unconstrained choice as the rings had to work with the existing stock pistons from the 1980's. In any case, the result works great. For example, probably the most stressed and most used boosted engine now runs with minimal or no oil control issues, whereas it used to blow out the dipstick and consume oil like crazy with the stock rings. Another turbo engine built with those rings has minimal oil consumption and blowby. The only way I've been able to make sense of this is that the second ring that the person selected for the ring pack (whether because it is gapless or despite of it being gapless) does a lot better job scraping oil off the bore walls than the stock second ring.

[user-30257]

It so happens that the engine that I'm primarily interested in has a big, big problem of way too much oil being sprayed on the bore walls. To remedy this, one of the most thoughtful people who's ever been involved in working with this particular engine designed a ring pack that has a second gapless ring. This wasn't a fully unconstrained choice as the rings had to work with the existing stock pistons from the 1980's. In any case, the result works great. For example, probably the most stressed and most used boosted engine now runs with minimal or no oil control issues, whereas it used to blow out the dipstick and consume oil like crazy with the stock rings. Another turbo engine built with those rings has minimal oil consumption and blowby. The only way I've been able to make sense of this is that the second ring that the person selected for the ring pack (whether because it is gapless or despite of it being gapless) does a lot better job scraping oil off the bore walls than the stock second ring.

Maybe their issue is stemming from other areas. Too much bearing clearance, too coarse of a hone. Too much piston to wall clearance, terrible oil pan, too much oil level.. etc

If a 6 inch stroke engine doesn't need them, what does? Imho it's a bandaid. Just like the BURR finish.

[ptuomov]

It so happens that the engine that I'm primarily interested in has a big, big problem of way too much oil being sprayed on the bore walls. To remedy this, one of the most thoughtful people who's ever been involved in working with this particular engine designed a ring pack that has a second gapless ring. This wasn't a fully unconstrained choice as the rings had to work with the existing stock pistons from the 1980's. In any case, the result works great. For example, probably the most stressed and most used boosted engine now runs with minimal or no oil control issues, whereas it used to blow out the dipstick and consume oil like crazy with the stock rings. Another turbo engine built with those rings has minimal oil consumption and blowby. The only way I've been able to make sense of this is that the second ring that the person selected for the ring pack (whether because it is gapless or despite of it being gapless) does a lot better job scraping oil off the bore walls than the stock second ring.

Maybe their issue is stemming from other areas. Too much bearing clearance, too coarse of a hone. Too much piston to wall clearance, terrible oil pan, too much oil level.. etc

If a 6 inch stroke engine doesn't need them, what does? Imho it's a bandaid. Just like the BURR finish.

This engine runs iron coated aluminum pistons on etched aluminum bores, so the piston to bore clearances are science fiction tight compared to the clearances that most people here run. It’s self evident that the issue is not the piston to bore clearances. It’s also not the rod bearing clearances, as those can be and are kept relatively tight due to the relatively rigid rod big ends, low redline rpm, and high compression loads.

The known underlying issues include very shallow oil pan due to minimal ground clearance and poorly placed head oil drain outlets. And many other issues, such as poorly designed breather system.

Things that I believe (and in some cases know) help are better crankcase breathers, oil pan spacer, various splash etc plates inside the pan, better oil drain holes drilled to pistons, and those custom second piston rings. Note that I am not saying those second rings help _because_ they are gapless, they may help _despite_ of being gapless because of being otherwise superior.

Given that I am not designing an engine from scratch, just looking for minimum modifications to get an existing engine to work better, well-sealing bandaid solutions are also desired and helpful!

[user-30257]

It so happens that the engine that I'm primarily interested in has a big, big problem of way too much oil being sprayed on the bore walls. To remedy this, one of the most thoughtful people who's ever been involved in working with this particular engine designed a ring pack that has a second gapless ring. This wasn't a fully unconstrained choice as the rings had to work with the existing stock pistons from the 1980's. In any case, the result works great. For example, probably the most stressed and most used boosted engine now runs with minimal or no oil control issues, whereas it used to blow out the dipstick and consume oil like crazy with the stock rings. Another turbo engine built with those rings has minimal oil consumption and blowby. The only way I've been able to make sense of this is that the second ring that the person selected for the ring pack (whether because it is gapless or despite of it being gapless) does a lot better job scraping oil off the bore walls than the stock second ring.

Maybe their issue is stemming from other areas. Too much bearing clearance, too coarse of a hone. Too much piston to wall clearance, terrible oil pan, too much oil level.. etc

If a 6 inch stroke engine doesn't need them, what does? Imho it's a bandaid. Just like the BURR finish.

This engine runs iron coated aluminum pistons on etched aluminum bores, so the piston to bore clearances are science fiction tight compared to the clearances that most people here run. It’s self evident that the issue is not the piston to bore clearances. It’s also not the rod bearing clearances, as those can be and are kept relatively tight due to the relatively rigid rod big ends, low redline rpm, and high compression loads.

The known underlying issues include very shallow oil pan due to minimal ground clearance and poorly placed head oil drain outlets. And many other issues, such as poorly designed breather system.

Things that I believe (and in some cases know) help are better crankcase breathers, oil pan spacer, various splash etc plates inside the pan, better oil drain holes drilled to pistons, and those custom second piston rings. Note that I am not saying those second rings help _because_ they are gapless, they may help _despite_ of being gapless because of being otherwise superior.

Given that I am not designing an engine from scratch, just looking for minimum modifications to get an existing engine to work better, well-sealing bandaid solutions are also desired and helpful!

After knowing the basic problems I hope you can address those, and prevent any future problems from arising.

A lot of what we learn is from others. But personal experience and tricks from others help us out tenfold. It is much how engineers make things more difficult than needed.

[groberts101]

Simply put, gapless rings allow you to use a thinner ring, any power you may have gained was probably from less friction. But then again adding an extra ring to the ring groove makes a heavier ring pack and a stack up of tolerance.
Why not just order the right piston and the thinner ring, and forget about gapless. If you are using gapless for better ring seal find a better machine shop, or get better at preparing bores.
You need a flat ring groove and a flat . As far as blowby, I have seen refreshed engines to reduce blowby make no more power and been slower at the track..

But take what I say with a grain of salt. I'm a nobody.

That is incorrect. Gapless ring designs inherently REDUCE the rings overall mass, thereby disallowing the ability to go really thin compared to a conventional full profile ring design. The gapless compression rings 2nd ring portion/mass(somewhat similar to the oil rings rails) does not add that same lost mass back into the main rings mass to fully gain back the same strength and heat tolerance as a single ring of similar mass. Obviously because they can twist and move slightly independently of one another. Like two 2"x4" put together without gluelaminating them together doesn't provide double the strength. Only fills the ring lands void and turns it into a gapless ring design by splitting the gaps away from each other.

But.. that's not to say those gaps will not eventually line up either. I have seen cranking compression and leakdown %'s slightly vary from one cylinder to another on seemingly perfect running motors and upon initial topend teardown.. guess what I see. Yep.. gaps were aligned with one another and the ring looked like any other traditionally gapped design. Call total seal up in a tizzy and they will quickly tell you that's completely normal and expected so don't sweat it because it's a positive sign that the rings are rotating as designed and required. Run it longer anf they'll move away from each other again. That's inherent design flaw(weakness is what lead me towards the childs & alberts stepped end gap design. But those much thinner filed/stepped/notched(whatever you want to call them) end gapped rings caused some durability issues for some guys so I stuck with the total seal design over the longer term. Pro's and con's no matter how you go with a ringed piston.

To me, and I'm just a nobody too, that intermittent pressure variation confirms the gapless designs ability to capture more pressure than the same ring set with a gapped design/when they are temporarily aligned. Now granted, I don't run high end 10,000 rpm race motors with gas porting, so all my a-b-a testing has been done on motors below the 600 horsepower range. Gapless rings work every single time.. street or strip. Claimer guys won't use them because they think it will be wasted money in the long run but there are a few out there who will take the chance at standing out in the field.

As for being slower on the track, I have heard others say similar but maybe the gapless rings potential cylinder pressure gains reach a crossover point where an increased potential for higher pumping losses starts overshadowing any potential gains in ET related to that potentially higher cylinder pressure?

Not saying total seal doesn't make em' really thin.. only that you can VERY easily scorch very thin rings to the point of overheating and twisting in the ring lands. The newer higher end steel gapless stuff gives more latitude in that regard but you still have some added limitations related to the gapless designs inherently reduced ring mass.

[Krooser]

I ran them on my 351-c dirt track engines... Arias pistons with the rings supplied by Arias. Also put them in the blown early Hemi I built several years ago... Venolia's with gapless top rings that came with the pistons.

They seemed to work fine... plan on using them in my redone 388 small block Mopar, too.

[RAMM]

The gapless design is a gimmick pure and simple. They leakdown and dyno test great at first but they all burn ton's of oil. Everytime. I track that closely and even on tear down and refresh the chambers and pistons show signs of excessive oil consumption. Also when I switch to a conventional or AP ring power goes up. Gapless is a scam -Even Jenkins tested this and found the same thing. J.Rob

[groberts101]

The gapless design is a gimmick pure and simple. They leakdown and dyno test great at first but they all burn ton's of oil. Everytime. I track that closely and even on tear down and refresh the chambers and pistons show signs of excessive oil consumption. Also when I switch to a conventional or AP ring power goes up. Gapless is a scam -Even Jenkins tested this and found the same thing. J.Rob

Burn ton's of oil? Lol.. they're probably the same damn ring part numbers your using for the gapped versions. So the gapless design itself caused your oil consumption issues? Maybe you're doing something very wrong if you expect the COMPRESSION ring to control oil?

And unless somethings changed since I last spoke with them.. Total seal just machines them from other off shelf parts to make their gapless design. Same goes for their AP stuff too.. just bought a set of AP maxseals.

And so what if Jenkins didn't like em'? I liked the guy too but I don't gauge every parts choice I ever made or will ever make solely on his experiences. Nobody knows everything about everyhing.. just the way it is because life's just too short to learn it all. In fact.. Kaase, Sherman and many others my brain can't remember right now have said they liked em' plenty good at one time or another for anything but all out full effort race motors.

In a nutshell.. if what you say about oil consumption was even remotely true.. more people would be having issues and that bad news would travel far faster than any good news ever would. Well.. that and I must be one lucky SOB because I've never once found that to be true on more than a dozen sets I've personally installed myself. Not to mention the dozens of others I've never seen blow smoke. Maybe it's time to play the lottery.

[Alan Roehrich]

I have never liked the gapless second ring. It always struck me as a very bad idea.

The gapless top is another matter. Done right, it is an idea with merit and good for the correct applications and uses.

Will the gapless second cause problems? Yes.

I do not think the gapless top will cause oil consumption problems by itself.However, if you use an oil ring with tangential tension that is too low, and it requires some compression ring leakage to blow the oil ring out, then possibly. That's not a gapless top ring problem, that's a ring package problem.

[ProPower engines]

WE used conventional rings sets for many years when we ran Winston west open comp stuff and that was during the trend to the gapless ring sets introduction and while we did try them at 1st we had issues till the bore finishes were worked on and after it was all said and done we found the gapless top rings with the 2 different ring materials did not work any better then a ring with a properly spaced radial depth and end gap.
We saw the same or even better leak down numbers using a 1/16 ring and back spacer to correctly gill the groove with lateral gas ports then the best gapless ring package for the same piston part number after 10 races.

Now the thinner .043 std. type top and napier 2nd rings while they seemed to do a bit better job again the gapless combos were no better in durability.

We did work with a ring manufacture back in the day and we were able to get the specific ring sets we needed and never had any issues with a conventional type ring set and we still work with them today to get the best sealing packages for specific applications and still after 3000 laps have less then 2% leak down which speaks volumes to the quality of there rings and dedication to a person that just plain understands rings in general to give us the best possible products without getting wrapped up in all the hype of the gapless ring deal.

And JMO but who ever thought a gapless 2nd ring was worth using based on the intended purpose of that rings real job needs their hand shook cause all they did was sell a useless product to guys that did not know better making a shit ton of cash for the company that sells them. And while they say they work and keep cyl. leakage down we must remember which ring really seals the cylinder from blow by and it ain't the 2nd ring now is it

Not saying that their product does not work at all in any application I am sure there is several applications it can work in but then so does a conventional ring set.

[ptuomov]

And JMO but who ever thought a gapless 2nd ring was worth using based on the intended purpose of that rings real job needs their hand shook cause all they did was sell a useless product to guys that did not know better making a shit ton of cash for the company that sells them. And while they say they work and keep cyl. leakage down we must remember which ring really seals the cylinder from blow by and it ain't the 2nd ring now is it

Not saying that their product does not work at all in any application I am sure there is several applications it can work in but then so does a conventional ring set.

The logic of running a gapless second ring would have to be better oil control in a problem application. That’s why we run a second “compression” ring of any kind in the first place, right?

In terms of high rpm blowby, the blowby doesn’t really by my understanding go thru the ring gap if the ring gap is anything sensible. It goes between the bore wall and the ring. I’m thinking that as long as the bore is perfectly round and the ring conforms to it, at high rpms gapless or traditional design doesn’t make any difference. Along the same lines, high rpm blowby in a worn engine doesn’t come from the ring gap expanding in a perfectly round bore. It comes from the bore having worn into a non-round shape. Oval not so much of an issue, but cloverleaf shape or something like that would do it. The ring can conform to that shape.

[swampbuggy]

AGREE to the above. Mark H.