Gapless Rings

[Bobby Fazio]

What are your thoughts on these? Do they have pros and cons? Also I think there is a choice between a gapless top ring or gapless second ring, any benefit there?

[carl hinkson]

Originally Posted by Bobby Fazio

What are your thoughts on these? Do they have pros and cons? Also I think there is a choice between a gapless top ring or gapless second ring, any benefit there?

Gapless top ring is a good deal..


The second I would not use as there is not place for the gases to go if its a sealed, Once you get pressure between the first and second ring to top is lifted by the pressure between the 2 rings.

Thats why most pistons have a groove between the first and second groove, Its called pressure seal groove or an accumulator goove. to give a place for pressure to build up so it will not affect the seal of the top ring.

[Alan Roehrich]

The gapless top ring is fine. Call Keith Jones at Total Seal and get his recommendation for your specific combination.

I do not use a gapless second ring, as it prevents any gasses that get by the top ring from escaping, that unseats the top ring from the bottom of the top land, causing it to flutter and leak. What little does get by will help the oil ring seal, and won't hurt anything. If the top ring is allowing much of anything to get past, the second ring won't help, even if it is gapless. The function of the second ring is to pull a vacuum on the cylinder, and remove any excess oil that the oil ring doesn't get.

[randy wilson]

I agree with all the above. And I've actually gained HP on the dyno, and ET on the track with a gapless top.

[Rick Leininger Jr.]

Depending on piston speed, a gapless top ring can be a benefit, or become a detriment.

[Mike Pearson]

I tried the gapless top ring and my results were not good. I went back to the standard .043 top ring.

[randy wilson]

Originally Posted by Mike Pearson

I tried the gapless top ring and my results were not good. I went back to the standard .043 top ring.

It is a strange deal. We always picked up a little with them, but it's hit or miss. Some people absolutely won't run them. I won't run without them. Now, I've tried the gapless second and would never recommend that.

[jmantle]

Originally Posted by Mike Pearson

I tried the gapless top ring and my results were not good. I went back to the standard .043 top ring.

I've run 3 ring combinations in the same engine,

conventional file fit, 5/64, 5/64, 3/16. Ran good, no oiling issues. (.060 over)

as above except .043 top with gas ported spacer, slowed down about .07, no oiling issues. (.070 over)

Gapless top, picked back up but now oils the plugs. (.080 over)

All were run with napier second, low drag oil ring.

This is a low rpm, under carbed combo so may not be the real world with a high rpm setup.

Jim Mantle V/SA 6632

[Ed Wright]

Originally Posted by randy wilson

It is a strange deal. We always picked up a little with them, but it's hit or miss. Some people absolutely won't run them. I won't run without them. Now, I've tried the gapless second and would never recommend that.

Randy, how wide (thick) non-gapless ring were you testing that against? Nobody runs .043" anymore, do they? .023" & .028" is what I hear most about anymore. Do they make gapless rings that thin now?

[randy wilson]

Originally Posted by Ed Wright

Randy, how wide (thick) non-gapless ring were you testing that against? Nobody runs .043" anymore, do they? .023" & .028" is what I hear most about anymore. Do they make gapless rings that thin now?

No, they don't make them that thin as far as I know. Our last Dart Buick had the real thin package, and I know they were not gapless. Someone else may know different, but I think the super thin rings are gapped. I still run quite a few .043 rings, in fact the only thin ring engine we've done was the Dart Buick. My experience with two ring, .043 top, then low tension oil ring, and .043, ,043, 3 mm, and the 3 ring thin stuff all pulled about the same vac at 20" with a wet sump. There's something there with the thin ring, but quite expensive. My saying is if the super thin rings beat ya, you're real close to kicking their ***. We ran gapless in all the .043 stuff.