Gapless rings

I've been using gapless 2nd rings on lightweight pistons for years. You can stand on the kickstart and leak down is much slower. The oil also seems to stay cleaner longer. So many people are concerned about cylinder sealing - I'm surprised that more aren't using gapless rings. I've had no trouble with them at all.

Good info Jim, Thanks for the post.

I've built three 880 engines and sold 2 sets of 880 pistons & rings, all procured from Kenny Dreer when he sold me a big chunk of his old inventory.

They are excellent and very easy to install.

Hi,
I was recently on the Total Seal website and I noticed per application (IE Norton motorcycle) that the 2nd ring was the gapless type. Is there any particular reason the top ring is not also gapless?

GB

I think the story goes that if you use a gapless 2nd ring at the top it gets fried and won't hold up.
I think they did come up with a gapless ring for use at the top,but it can't be used with a gapless 2nd ring.The gapless 2nd ring causes the top ring to unseat and leak.

For about 30 years,the rest of the world has been getting better results by INCREASING the gap on the 2nd ring.It's become normal practice on new car engines,and results in increased power and reduced oil consumption.

Here's a read,with good comments near the bottom of the page:http://www.speedwake.com/forums/archive/index.php/t-34413.html

Some turbo car owners report ring seal failures with gapless rings.

Why this is I don't know. I do know that ring seal depends in large part on pressure behind the ring which pushes the ring out and into the cylinder wall AND down onto the lower ring land. This is exaggerated in the Dykes type "L" shaped rings used in the lower dynamic pressure application of two strokes. In boosted applications, especially when detonation occurs, the floor of the ring lands sometimes crack or bend and then ring seal is compromised.

In the gapless design, it may be that the overlap of the ring onto itself, under boost, introduces a point of additional friction, of the ring against itself, that interferes with full expansion of the ring out and against the cylinder wall. That is, there might be less lubricity ring to ring than there is ring to land such that the overlap portion lags in its expansion out to the wall.

I wonder why the top ring is conventional and only the second is gapless. I mean why not both? There must be something better about the conventional ring's ability to handle higher pressures or combustion heat.

IRRC Ms Peel ran TS gapless top ring just fine. Gapless rings mainly help lower rpm sealing and not needed or helpful in upper band as nil time to blow much through the gap. Boost helps seal top ring by pressure behind ring so gapless top ring not needed. in gap rings a bigger gap in 2nd ring than top allows more pressure difference on top ring to seal tighter by combustion pressure. TS site has info on why a top or 2nd gapless ring and tech will talk to ya too.

Gosh this reminds me of arquement with my brother which would ya like least to be shot with, 357 or 45, he finally gave up and said shit just surprise me!

QUESTION:
What advantage does the gapless top ring offer over the gapless 2nd ring?
ANSWER:
The Total Seal gapless top ring is the natural evolution of the gapless second. By moving the gapless ring to the #1 ring groove we effectively seal the cylinder closer to the combustion chamber. This not only increases the cylinder seal on the compression and power stokes but also improves the ring seal on the intake stroke resulting in better cylinder filling on a normally aspirated engine. The increased amount of force generated by the combustion process in turn delivers a greater amount of energy to the crankshaft. The choice is yours and either ring offers superior cylinder sealing.

Click to expand...

Gapless 2nd rings work better than regular rings in Nortons because:

The gapless 2nd rings provide a better seal and reduce blow by on Nortons as long as you don't rev beyond 8700 RPM. Above that you can get ring flutter. This problem doesn't apply to Nortons because Norton's don't rev that high (for very long - as in once). So yes - a gapless 2nd ring is better for the street and all around riding.

A gapless top ring is not recommended for the street because the vacuum with the throttle shut is increased to the point when oil wants to get sucked into the motor from any available source such as head bolts etc. 9000+ RPM Racers don't care about this.

The wider 2nd ring gap used by two ring manufactures that I know of has debatable pros & cons depending on who you are talking to. It could likely be causing more blow by and oil burning. I have received complaints about the gap on 2nd rings being too wide but never a complaint about the gapless 2nd rings. Pro stock racers are one group that sees a loss of HP with the wider 2nd ring gap.

With gapless 2nd rings expect an increase in performance in the lower & med RPM range which is what Nortons are all about. Don't expect an improvement at redline.

I have been running Total Seal rings for about 4 years. The first thing I noticed is that the oil stayed clean ( like new) all season. and I never had any oil consumption. This is with a supercharged 850.

Also to note :Total seal recommends running valve guide seals on the exhaust valves also!
I questioned this logic, but did it anyway and have seen no negative effects like excessive guide wear.