Gapless Rings

[Hill Top]

Any draw back to using gapless rings? I'm wondering why they don't use them in factory engines.

 

[Will L.]

Expense. Just like why the don't have minumun filed fit rings,fully balance, fully ported heads intake and exhaust, or why bearing tolerances are so much instead of keeping them all at minimum.

Even if the theory was to allow some compression bypass through the rings, any performance builder knows filing the rings to the minimum clearance makes a difference in more power, more mpg, and longer engine life. Yet mass production has a wide allowable tolerance. It just takes too much time and more expense to do the extra stuff.

 

[WarWagon]

The factory line worker, boring job BTW, is doing a crossword puzzle with their other hand while dropping the pistons in. A hand built engine would cost more than the vehicle new: see race car engine prices.

I have 36K extreme miles on gapless rings and still no blowby. I have extended my oil drain intervals to 5000 miles. Formerly 3000 miles was too many miles per UOA. I can see the marks on the dipstick awhile after an oil change. The marks start to go away near 5K miles: what oil looks like after startup without gapless rings. The project 6.5 truck has 1000 miles with gapless rings.

It's important to get a good seat of the rings from the word go. Stomp it, but, vary the load and RPM. You need full throttle ASAP to seat the 2nd ring, but, not extended time at full throttle. Seen several ring sets that didn't fully seat the 2nd ring.

So I haven't broken my engine with them in. What more do you need for proof there isn't a downside?

They take longer to install and are "new" with some shops afraid of them (the unknown).

 

[MrMarty51]

The factory line worker, boring job BTW, is doing a crossword puzzle with their other hand while dropping the pistons in. A hand built engine would cost more than the vehicle new: see race car engine prices.

I have 36K extreme miles on gapless rings and still no blowby. I have extended my oil drain intervals to 5000 miles. Formerly 3000 miles was too many miles per UOA. I can see the marks on the dipstick awhile after an oil change. The marks start to go away near 5K miles: what oil looks like after startup without gapless rings. The project 6.5 truck has 1000 miles with gapless rings.

It's important to get a good seat of the rings from the word go. Stomp it, but, vary the load and RPM. You need full throttle ASAP to seat the 2nd ring, but, not extended time at full throttle. Seen several ring sets that didn't fully seat the 2nd ring.

So I haven't broken my engine with them in. What more do you need for proof there isn't a downside?

They take longer to install and are "new" with some shops afraid of them (the unknown).

And with that, I will try the gapless rings on the next engine that I rebuild.
If I can find the ASE tests and reports, I will start a thread about to hone, or, not to hone cylinders.

 

[WarWagon]

@MrMarty51 Total Seal "If you have any questions about how your cylinder should be honed, please contact us at 800-874-2753" Unless you are dropping them in an Optimizer or P400, used or new, the (any) machining cost on a GM casting isn't worth it plus OS piston cost. They run just fine with a hand drill and stone set. Just have to break the glaze. Used the hand drill on both of my gapless ring installs both perfect bores and highly questionable. YMMV as you may know a machinist that will work for beer. I don't.

 

[MrMarty51]

@MrMarty51 Total Seal "If you have any questions about how your cylinder should be honed, please contact us at 800-874-2753" Unless you are dropping them in an Optimizer or P400, used or new, the (any) machining cost on a GM casting isn't worth it plus OS piston cost. They run just fine with a hand drill and stone set. Just have to break the glaze. Used the hand drill on both of my gapless ring installs both perfect bores and highly questionable. YMMV as you may know a machinist that will work for beer. I don't.

I sure wish that I did know a machinist like that.
Only one local shop that will bore cylinders and fit pistons. So much for every 0.010 over bore.
He might though, cut a deal if I fit the pistons, using His tooling.
the local college would do it too, for free, if they were in the engine rebuilding stages of the classes.
So, it would probably be wise to get the Optimizer or the P400 rather than spend money on the stock GM block and heads, i`m guessing.

 

[Jaryd]

I sure wish that I did know a machinist like that.
Only one local shop that will bore cylinders and fit pistons. So much for every 0.010 over bore.
He might though, cut a deal if I fit the pistons, using His tooling.
the local college would do it too, for free, if they were in the engine rebuilding stages of the classes.
So, it would probably be wise to get the Optimizer or the P400 rather than spend money on the stock GM block and heads, i`m guessing.

Very wise to go with a takeout Optimzer or even better, a p400

 

[3500GMC]

I can say the Sealed Power pistons for 6.2 & 6.5 (and others) are currently mfgd in India and LACK the steel keystone top ring land that interlocks in the piston casting.. They're made entirely of whatever aluminum they scare up over there. Consequently they are much lighter so balance becomes an issue too. That's not good enough IMO. So building a good fresh 'rebuild' (overbore) is tough to do.

The gapless 2nd ring is worth a shot for these old oil burners we run.

There's been some high rev/perf gasser builders that have scoffed at the gapless 2nd rings, they claim the pressure trapped between the top and second ring tends to unseat the top ring.

I'm willing to bet things were overlooked on the build, like say, low tension thin as foil 'race rings' that brings in a whole nuther set of variables.

 

[Will L.]

There are Lots of racers winning that use gapless rings. A bunch of people have been doing both compression rings gapless, they are the ones popping rings off. There is also people going for minimal clearance cuts for the rings that are having issues. Some people have to take a good thing and tey to milk every drop out of it, which can be devistating. Follow the instructions by the people making the rings and you will have good results.

 

[3500GMC]

Absolutely yes. If you butt a ring, game over, with any engine.

Traditionally the 2nd ring acts as an oil sraper and is made with a tapered face which is not ideal for sealing compression.. Are these gapless rings still a tapered face?

 

[Hill Top]

Are the gapless rings doing more than making you feel better by having prettier oil?

 

[schiker]

I think they are good for a few horse power. In comparison production ring gap is allowing more blowby and loss of efficiency, file to fit is better, gapless is best.

There is documented improvements in gas engines. Don't know if Turbo is better would think so. Better seal on exhaust stroke. That might offset the lower rpm of diesel vs gas to give same improvement. Better seal on compression stroke might help starting????

Lower soot in oil is pretty big IMO. Worn out oil contaminated with soot doesn't seal the rings as well IMO. I get less of a puff of diesel smoke on launch with fresh oil change. Note manual transmission launch its easier to notice.

Here is one study.

http://www.strokerengine.com/GaplessRings.html

 

[WarWagon]

Are the gapless rings doing more than making you feel better by having prettier oil?

The lack of blowby is pretty big. The rings go away before anything else on these engines. (Aside of cracks or head bolt/gasket failures.) This is one well known item to check the health of the engine before buying one.

IMO you are missing the point of "prettier oil". Doubling the miles I get out of oil before soot ruins it to a thicker grade is a verified proof of less blowby and all the garbage in the combustion chamber getting past the ring gap into the crankcase. Small NA precups and all the fuel I can throw at it from a stock IP in hot thin air should add more of a "wow" factor for as dirty as this engine runs. (Our IDI 6.2-6.5 engines are fairly dirty to begin with having a 2500 mile oil change in the owners manual. ) Some days Patch actually fails emissions: the other days the soot blows out their sensors so bad they can't get a zero reading to officially fail it. I have been held up as they first retest other failed cars, from Patch being tested at the same time, then try and test Patch. I really need the smoke puff limiter... (Why they make one "snap" floor it when they only read the smoke at WOT Full RPM is plain stupid.) Regardless the high stall converter cleaned up the smoke a lot as I don't run the engine down low lugging smoke so much anymore.

More air kept in the combustion chamber means more power and less for the CDR system to choke the engine up on.

I have posted UOA results and the like in the above noted thread of mine. All this simply shows my experience with something new and improved for our forgotten diesels. Hopefully this gives you some better understanding for any decisions you may make or just discussion.

 

[Hill Top]

The lack of blowby is pretty big. The rings go away before anything else on these engines. (Aside of cracks or head bolt/gasket failures.) This is one well known item to check the health of the engine before buying one.

IMO you are missing the point of "prettier oil". Doubling the miles I get out of oil before soot ruins it to a thicker grade is a verified proof of less blowby and all the garbage in the combustion chamber getting past the ring gap into the crankcase. Small NA precups and all the fuel I can throw at it from a stock IP in hot thin air should add more of a "wow" factor for as dirty as this engine runs. (Our IDI 6.2-6.5 engines are fairly dirty to begin with having a 2500 mile oil change in the owners manual. ) Some days Patch actually fails emissions: the other days the soot blows out their sensors so bad they can't get a zero reading to officially fail it. I have been held up as they first retest other failed cars, from Patch being tested at the same time, then try and test Patch. I really need the smoke puff limiter... (Why they make one "snap" floor it when they only read the smoke at WOT Full RPM is plain stupid.) Regardless the high stall converter cleaned up the smoke a lot as I don't run the engine down low lugging smoke so much anymore.

More air kept in the combustion chamber means more power and less for the CDR system to choke the engine up on.

I have posted UOA results and the like in the above noted thread of mine. All this simply shows my experience with something new and improved for our forgotten diesels. Hopefully this gives you some better understanding for any decisions you may make or just discussion.

As always WW a great response! Thanks!