3-5/16" Piston Rings
 

Does anyone know a current good part number for 3-5/16" Piston Rings (0.125" oversized) for the ~42-48 pistons. I have a set of aftermarket three ring pistons that uses the older ring package that was the same on the factory Ford pistons in 42-48.


I need a set of rings where it has 3/32" top rings and 5/32" oil rings preferably with the more modern three-piece oil ring.

It seems to be hard to find this particular combination. I can easily find 3/32 top rings with 3/16" oil rings.

Re: 3-5/16" Piston Rings
 

For piston rings check with Egge machine in California bedsides making pistons they are a good source for piston ring sets.

Ronnieroadster

Re: 3-5/16" Piston Rings
 

If it turns out that the 5/32 rings really are not available it is probably possible to skim out the ring grooves on a lathe and use the 3/16" rings.

Re: 3-5/16" Piston Rings
 

contact David Reed at Auto Gas at 410-398-7340. They can supply any rings you need. Got the contact from Egge.

Re: 3-5/16" Piston Rings
 

Jack,

Is David Reed's business called Auto or is it Otto Gas?

Re: 3-5/16" Piston Rings
 

Otto Gas https://ringspacers.com/

Re: 3-5/16" Piston Rings
 

Yup,Otto. My bad

Re: 3-5/16" Piston Rings
 

Might mention that with a modern three piece oil ring, a 4th ring is NOT needed in the lower groove. It is perfectly OK to leave that groove empty. There is an urban myth that says the 4th ring "stabilizes" the piston but that is "poppycock", nonsense, false, etc. Rings all float freely in their grooves so cannot support a piston in any way, shape, or form. All a 4rth ring does is add internal friction which reduces power.
Instead, the piston must support the rings at 90 degrees to the cylinder wall to maintain good ring seal.

Re: 3-5/16" Piston Rings
 

I concur. On my last build, I had a set on new 4 ring 3 5/16" pistons, rings and pins I got on a real good deal from Speedway Motors. I entered into a lot of discussions, both here and on the H.A.M.B., and the consensus was that the 4th (bottom) ring was unnecessary and an actual detriment. I built the engine without the fourth ring, but had it balanced. Everything turned out as it should have, so I recommend leaving the bottom ring out.

To paraphrase what was said above, "the piston supports the rings, not the other way around".

Re: 3-5/16" Piston Rings
 

I have a brand new set of Ross 3-ring 125 over pistons for a 4” crank for soneone who needs a set - pm me.