[SEL] Piston Ring Size

[curt at rustyiron.com]

Kerry,
I don't know if this would be helpful, but I documented rings I made for a
couple of engines back in '09. The gap was ,625. On the diameter that
works to about 0.2". So the rings were about 0.2" larger than the bore in
the relaxed condition.

The measurements you describe sound about right. I question the material
and the radial thickness. As I recall I used Grade 30 cast iron. That
30,000 psi material. Nice and soft.

See
<http://www.oldengine.org/members/holland/images/MakingPistonRings/Thumbnails.html>

Curt Holland
Bessemer City, NC

> G'Day All
> I just pulled the piston out of an engine that I have that never had
> very good compression, bore not brilliant but its the rings I am
> questioning as when I pulled the piston out two of the rings looked too
> big and requires a lot of force to push them in by hand to anything like
> the piston size. The piston is 5.5 inch in Dia and the normal dia of the
> outside of rings is 5.75, is that two much, width is 3/8.
> Thanks for suggestions
>
> Kerry
> Lithgow NSW Oz
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