im going to finally pull apart my engine and re-ring , etc...

What are the pros / cons of gapless rings ? Ive never used them. The engine is .030 over 440 block , 10.8:1 with Ross flat tops , pump gas and n/a .

Gapless 2nd, don't do it. If the compression gets past the first ring you don't want it building up between the rings or it'll unseat the top ring yet again, costing power. 2nd ring is meant to be a scraper only. Gapless top has it's applications. Alcohol burners, should keep the oil less diluted. Low rpm engines, should help keep the compression sealed. On high rpm I have my doubts that two rings can seal better than one single as there are more pieces that need to seal against themselves. Leakdown will typically show an improvement but at rpm, the amount of leakage past the gap is so minute it's just about not worth mentioning.

I tried gapless second, didn't help at all. Have been running file fit rings, runs pretty good.

I have been using total seals gapless top rings for many years and have had great success.I have a 68 dart running 9.70 @ 140 mph with a 440 not stroked with eagle rods and ross pistons topped of with some indy heads,not the fastest by far but pretty decent for racing at 4800 feet.

Ive used the gapless seconds.
Very happy with them. Either people like them or they dont.
Can tell you after a many yrs, albeit not that many miles, street and track, less than 2% leakdown on one hole, rest were less than that.
Built that back in '85, still together, waiting next project. One of those builds that gave more than expected.
People say static leakdown means little, cant figure that one as its a good indicator for race teams.
Total Seal, I'm sold on them.

it got irritating to me this year telling people that my ring seal in my hemi sucked,, they would all ask well,, what does it leakdown?? like that meant something... leakdown will tell you if a valve is bent or seat is beat out,, blown head gasket,, moly on ring flaked,, piston broke,,,

as far as ring seal once the engine is running,, leakdown means nothing


a pro stock guy i know used gapless rings,, just switched to a single gapped ring and picked up 20hp,, by single i mean one top ring,,, where as the gapless is two rings,, it had a 2nd ring in both applications

ive messed around with 2nd ring gap and seen nothing but had piston issues,, i need to readdress if more 2nd gap helps seal,, i know a tighter gapped 2nd ring is worth no power, just leaks down better. ive gapped 2nd rings at .050 and .012 seen no difference

Is the thinking that seal improves or there is not enough time for blowby to have an effect?
Honest question.

There are those engine builders that love them and there are those that don’t. It’s hard to argue either side of this because each has their point of view.

But the theory is simple - don’t lose combustion gas through a ring gap.

All I can say is that engines I have built using gapless rings:
* First - the cylinder hone is very important to using gapless rings. It is not the same as a normal ring.
* They can easily be installed wrong because of the angled gap that still must be filed and checked.
* These motors have a very consistent leak down even after many miles and passes on the strip.
* I use only a gapless top ring and a hooked groove or napier second ring which acts like a one way valve for trapped gas.
* I have measured a net improvement on the dyno doing an A to B comparison.
* In alcohol motors the oil stays cleaner.
* I have had problems getting the rings to seat.

But because of the special hone requirements (the final hone must be very smooth), and seating problems if the engine in not dynoed, I usually do not use a gapless top ring for street motors and mild bracket engines.

thanks for the advice .

i will just stick with some good file fit rings .I will be putting those in soon.

this motor has around 3 , HALF seasons on it and very low street miles--maybe 50.

is the bore hone something to worry about in my situation? .030 over 440 with moly top rings .

i might have the block re-checked for cracks and while its there i can have the shop re-do the hone

Gapless 2nds can tend to hammer the top ring against the ring lands , can also impede oil scavenging through the oil rings , i found all oil rings 'sticky' in the lands when using gapless 2nds , have now changed to Napier 2nds.

That's why I ONLY use Napier second rings with a gapless first.

I just got my Total Seal rings in yesterday.Advanced Profiling Steel rings,Maxseal gapless top ring,Napier style 2nd ring.

There is a lot of people on here that really know this stuff so I have a question.
Does having your pistons coated help? Or maybe it should be is it worth the money in a Race-Engine?

Coated pistons don't affect ring seal, but they do help reduce piston skirt scuffing. I coat all pistons whether street or race. There's no negative as far as I'm concerned.

Gapless top rings have worked great for me as long as I started with the correct hone finish. Other people have issues with gapless rings but on the engines I looked at, they didn't take the extra time to get the hone right. Follow the instructions and you'll love them.

How many times have you pulled an engine down to find all rings have moved round the cylinder alingning the gaps? , every time i pull the pistons i find the two part gapless ring along with the other rings have moved around & ring gaps have alined themselves , plus the fact the rail part of the gapless ring (bottom ring) has a hard job tranfering heat into the cylinder wall , plus the fact there no different in thickness than an oil rail.

I ran the gapless 2nds on an N20 motor , did'nt wanna take a chance using a gapless top bearing in mind any heat or detonation destroying the thin rail that makes up the gapless ring.

I would use the the Total Seal AP top ring along with a Napier 2nd for NA motor that's gonna see any power.

Well... I see several different opinions of course...


The leakdown argument----i really dont get that.

SO--heres what my leakdown showed last spring :

20-34% leakdown . some cylinders were 34% !!

so...leakdown believers : i need to re-ring.I agree .

and leakdown doubters = im totally fine (i find that had to believe)

Not sure what I can add other than I have the TS "gapless" top rings in my Challenger's engine. I built it myself and it was my decision to run 'em, regardless of the "leakdown debate" that always comes up.

The previous incarnation of this engine was built by someone else using Child & Albert's Z-gap "gapless" 2nd ring. I can say after about 4000 miles of street & strip use that the engine was showing leakdown #s in the 4-5% range for all cylinders, other than the two that were experiencging valve sealing issues.

After doing some research on my own, I decided to stick w/ a "gapless" design, only switch to the top-ring approach. I wish I could give some hard facts re: either before / after results between a traditional ring design and these and what I'm using now, but I can't. The comparisons I've seen described here or elsewhere have never been conclusive IMO and weren't necessarily what I thought were applicable to my application.

As far as the "leakdown doesn't mean anything" perspective... I'll have to fall back on the late Smokey Yunick's position that an engine showing higher than xx% of leakdown is an indication of sealing issues. Maybe the test itself is flawed, but if the before #s are that much lower than the after #s, it's got to be showing "something" isn't right.