What is the advantage of two rings over the single ring? Does it seal better therefore giving a better power stroke and more hp?

Gryohead
I believe thats the case. more compression therefore more power

Does the two rings do anything for the rpm, or does the extra ring cause enough drag to not let the engine turn up any faster.



Gryohead

gryohead
I dont believe that the second ring drags enough to offset the added compression
more compresion =more power

The 2nd ring was eliminated in very high revving engines because of drag.

This puts a lot of extra stress and wear on the top ring.

For low revving engines, 8,000 rpm and less, the 2nd ring adds power and longevity.

I also like to run Opti-2 oil at 75 to 1.
It's recommended at 100 to 1 but I have noticed extra power in my chainsaws at 75 to 1.
I'm guessing it's because on the better ring seal.

ralphbf
are you talking about an engineered engine or is this a tunning trick employed by someone
building race engines?
this is a new one to me, I understand about drag\friction but what about the lost compresion
and extra wear and tear on the piston due to skirt slapfrom only having the piston supported
by one ring?
like I said I get the drag angle but it just doesnt seem logical,"remove a ring and gain power"?
most things that seem to easy usually are
but I like to have an open mind I guess I could be wrong about this ring thing........maybee,

The rings do not support the piston, they only serve to seal against excessive blow by due to clearance between the piston and sleeve or cylinder. The rings actually float in the ring groove on a thin layer of oil as does the piston in the cylinder.

In the early to mid seventies when I was giving road racing a try, "Guys" riding large 2 strokes, like the Kawasaki 500 triple
Were removing the bottom ring and lowering their elapsed times on the track.

I rode a 250 Kawasaki Samari in the sportsman class and seemed to run better with both rings.
My engine was almost bone stock while the 500's were ported had different carbs and tuned exhaust.

I always assumed they ran better because of less friction, and the two rings on my bike ran better because it was more efferent.

And the middle ground was beyond my under standing.

There is probably a "break even" point there somewhere that would be dependent on the rpms. How about if someone with more time than me does some tests?? Wouldn't be too hard to do... Just a few different size props, a twin ring engine that you could just leave out one ring, and an afternoon of testing...

AV8TOR

Ralph is correct. Removing the bottom ring was a common tuning trick. The bottom ring was considered to be going along for the ride at high RPM. Pistons would not last quite as long and starting compression would be less.

Bill

I could see where a second ring could benfit a 4 stroke engine to control oil useage to wipe the oil from the cylinder walls, but that is in 4 strokes.



Gryohead[:-]