School me on Rings

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Jan 18, 2013 | 07:29 PM

#21

wht97ws6ta

TECH Apprentice

Joined: Dec 2008

Posts: 372

Likes: 1

From: Kinston North Carolina

Quote:

Originally Posted by bowtienut

While theoretically the gapless concept is "best", I'm still not convinced of it's real world merit. No data to support that, just my observations of a few reputable builders who aren't very high on them. If I were looking for every advantage without regard to cost, I could be talked into using them.
I'm more inclined to believe the findings of somebody like John Lingenfelter (said any gains were lost in the noise) than a magazine "testing" one of its advertisers' products. Perhaps they've gotten better since the initial designs?
Hopefully somebody responds with some data or source to get me more excited about them

I'm not sold on them either. When you think about what actually goes on with a ring and how it works the gap really seems to be there for other purposes than to allow for expansion. To rely on just the radial tension of the ring to seal the extreme pressures of the combustion process is a bit of a tall order in my opinion. I'm pretty sure that the gap allows combustion pressure to enter in the ring land of the piston where it gets behind the ring and forces it against the cyl wall. This is one of the reasons why the radial thickness of the ring is smaller than the depth of the ring land in the piston. You will also notice that most of your top rings have a bevel on the top inside of the ring. That would most likely be there to allow the pressure in the ring land to push down on the ring against the bottom of the ring land. Otherwise pressure would get under the ring and cause flutter. Good evidence to me that that's how rings work is the top ring tends to inflict more wear on the bore at the top of the bore where the combustion happens and generally most all motors with a lot of miles will wear the bore at a taper and will be big at the top. I'm no genius but that's just my 2 cents.

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