Gap-Less Rings : V-Twin Forum: Harley Davidson Forums

econnor · 09-13-2009, 03:05 PM

I just finished doing leak-down and compression tests on my 96" evo. The results are very surprising. less than 2% leak-down on both cylinders, compression was 219 and 221.

I built this engine in 2004 and have never had a speedometer on the bike. I have ridden this bike from eastern North Carolina to the Pacific ocean twice, Daytona three times and many miles locally.

The engine was built using Total Seal rings with a gapless second ring. At the time that I built this, many of the big shops recommended Hastings rings or other conventional rings.

I was thinking of doing a rebuild, but not anymore.

Has anyone else here used gapless rings and what where your results and experiences?

econnor · 09-15-2009, 08:14 PM

nobody has used gapless rings?

Lakerat · 09-15-2009, 08:43 PM

Nobody else has responded so here goes something for you to think about.
I won't use them because an NHRA engine builder I know said that you will continue to get good leakdown numbers until the cylinders wear to a point where the rings will not make up the gap between them and the cylinder walls. By the time you get a bad leakdown reading, the engine is a boat anchor. His opinion and he generally knows what he is talking about.

TXCHOP · 09-15-2009, 09:58 PM

I am running them in my build based on a recommendation from Chas at Axtell. My leakdown numbers are great(about same as yours) and ccp still the exact as day one. So far no issue noticed and since i am pulling my heads off over the winter for a slight comp bump i plan on inspecting them really well.

A racecar engine builder told me they are great rings for sure. If on the off chance there is a problem with your top rings only disassembly would tell the story though.
My rings were C+A.

econnor · 09-15-2009, 09:59 PM

You are right, that is something to think about. Seems to match the results I am seeing on this engine. Leakdown is nothing, and engine runs very strong. I don't understand the part about the boat anchor. In a Harley engine, if the cylinders get to be that worn, then they just get replaced. The rest of the engine can easily be brought back into spec.

Would like to hear more.

Hillside · 09-17-2009, 07:01 AM

We have used them before, but have heard the exact statement that you made mention of as well.
Scott

lowriderglen · 09-17-2009, 07:15 AM

I have a 4 3/4" stroke 3.505 bore evo with approx 20,000 miles on it and it still runs very good and leaks less than 2% using the Total Seal second ring. I have not installed a conventional set to do a comparison on the dyno. I do know of a HD shop that installed a Total Seal second ring in a 114 and lost 15 hp. They reinstalled the conventional second and picked up the 15 hp. Explanation???

TxChop--Is the C&A ring that you are using the Zero Gap?? It has been one of my favorites but is very hard on cylinder walls due to the radial tension.

dog155 · 09-17-2009, 07:36 AM

Quote:

Originally Posted by econnor

You are right, that is something to think about. Seems to match the results I am seeing on this engine. Leakdown is nothing, and engine runs very strong. I don't understand the part about the boat anchor. In a Harley engine, if the cylinders get to be that worn, then they just get replaced. The rest of the engine can easily be brought back into spec.

Would like to hear more.

Agree about the boat anchor thing.Gapless rings? have always wanted to but never have tried them.Great reading about them.

Hollywood63 · 09-17-2009, 09:13 AM

I tried them in a mild 80 inch and had to pull them out because they wouldn't seal. They would puff smoke on decel???

Dr.Hess · 09-17-2009, 04:58 PM

I have heard a lot of people complain that that didn't work in their motors. Mostly in the import realm, not HD, but I have heard enough biatch about having to tear their motors down and put in regular rings that I don't want to mess with them. Hastings rings have always worked for me.

Mavaholic · 09-17-2009, 06:50 PM

Never built a Vtwin but used them in my 302 in my Maverick. Took a long time to seat but going good for 7 years now, from what I remember honing technique has a lot to do with how well they seat.

gsxrboy96 · 09-17-2009, 07:23 PM

I use them in every car motor i build thats gonna be a nitrous oxide application, other than that, its overkill and hurting your wallet to run these rings, a standard moly ring will suffice in nearly every other application.

econnor · 09-17-2009, 08:55 PM

I should have mentioned this in my first post. One of my riding buddies has a 96" very similar to mine, although our mileage is different and he has Hastings rings. I have allot more miles on mine than he has. We did a leak down on his engine as well, using my gauges. If my engine showed less than 2% his showed about 9%. His bike runs well, burns no oil, but does not have nearly the power I have. We attribute that to my heads (Baisley Hybrid), although in all honesty, he has STD heads that are very good.

When we built these engines we were running neck and neck. But over time I ha ve been getting faster and faster compared to his 96". I would like to think it is because I am so meticulous in keeping my bike in fighting shape. But can't help but think the gapless rings have something to do with it.

Ed

rbabos · 09-17-2009, 09:39 PM

Quote:

Originally Posted by econnor

I should have mentioned this in my first post. One of my riding buddies has a 96" very similar to mine, although our mileage is different and he has Hastings rings. I have allot more miles on mine than he has. We did a leak down on his engine as well, using my gauges. If my engine showed less than 2% his showed about 9%. His bike runs well, burns no oil, but does not have nearly the power I have. We attribute that to my heads (Baisley Hybrid), although in all honesty, he has STD heads that are very good.

When we built these engines we were running neck and neck. But over time I ha ve been getting faster and faster compared to his 96". I would like to think it is because I am so meticulous in keeping my bike in fighting shape. But can't help but think the gapless rings have something to do with it.

Ed

Not really. Think about the time frame that a gap would have to leak at 6k rpm. It's practically none existant in rings with correct gaps. Mind you as the regular rings wear the gap increases , you will have a slight advantage in power. Very slight though. I've used these rings back in the 70s and at the time oiling issues were a concern. Seal, they did well, but it seemed the thin backup ring worked much like an oil ring scraper. Not a good idea for the top of the piston. Several people had tried gapless in first and second grooves until it was determined this is a disaster for lubing the cyl. Warning to use only for second compression ring on piston soon followed. Never had problems myself with their use in air cooled vw aircraft conversion engines , but most likely wouldn't pursue them any more at this time.
Ron