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Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 3:05 pm
by frnkeore
I have several sets of older FE & SBF pistons w/rings, that have ring grooves for either .078 x 2 or .078 x .093.
I was thinking that I could face them in a fixture with a bore size recess and center clamp and face them to .040 or .060. It would take a little tension off of them, too.
Anyone done anything like that?
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 4:24 pm
by In-Tech
Yes, but you want to use a surface wet grinder with a magnetic table so they are dead flat. Hit up a tool and die shop.
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 5:04 pm
by frnkeore
In-Tech wrote: ↑Tue Jan 24, 2023 4:24 pm
Yes, but you want to use a surface wet grinder with a magnetic table so they are dead flat. Hit up a tool and die shop.
I'm not sure what your saying. I have a machine shop and was a sub-contractor for the aircraft industry for many years. It would still be flat and would be cut, captured in a recess of bore size.
I'm not talking about making the rings a different size, across whole the surface, just the area that is outside the ring lands. The rest of the ring would locate normally.
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 6:45 pm
by In-Tech
I see what you are saying now. I suppose it would work if you can put a decent radius on it. It kinda scares me to think about that fracture point though. I would think to surface grind and use a spacer would be a better approach. Probably a good idea to talk with Akerly and Childs and/or Total Seal.
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 7:13 pm
by Tuner
Sort of like a Napier ring but without the taper face? Would you narrow it (cut it) on the upper or lower side?
https://www.highpowermedia.com/Archive/the-napier-ring
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 7:28 pm
by In-Tech
Yes, Tuner. My thoughts were it would be fine on the second ring ground as a Napier cut. I worry a bit about the top ring especially if you can't twist that top ring without breaking it.
I've done plenty of Dykes compression and Napier second rings in severely limited circle track classes but the pistons had to be made for that. It appears he is trying to make some use of old inventory. To me, not worth the effort. To each his own
https://www.highpowermedia.com/Archive/the-dykes-ring
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 8:07 pm
by frnkeore
Yes, that's it, exactly.
Would cut the bottom side with a .015 radius, since there will only be ~.020 per side clearance to work with.
It's a simple process. You just bore a recess, the depth of the finished ring face, thickness you want, to the diameter of the cylinder bore. Drill & tap a hole, for a bolt and then, bolt on a cap the diameter of the ring lands and cut it. Very ridged set up and the ring can't go anywhere, while making the cut.
Re: Cast Iron Ring Mods
Posted: Tue Jan 24, 2023 8:33 pm
by Tuner
In-Tech wrote: ↑Tue Jan 24, 2023 7:28 pm
Yes, Tuner. My thoughts were it would be fine on the second ring ground as a Napier cut. I worry a bit about the top ring especially if you can't twist that top ring without breaking it.
I've done plenty of Dykes compression and Napier second rings in severely limited circle track classes but the pistons had to be made for that. It appears he is trying to make some use of old inventory. To me, not worth the effort. To each his own
https://www.highpowermedia.com/Archive/the-dykes-ring
Sounds to me like the intention is to eliminate some ring and cylinder wall contact area to reduce friction.
Re: Cast Iron Ring Mods
Posted: Wed Jan 25, 2023 1:23 am
by Momus
I would do it in a flash, fixtured the same way with material taken from the undersde.
Re: Cast Iron Ring Mods
Posted: Wed Jan 25, 2023 3:01 am
by frnkeore
Tuner wrote: ↑Tue Jan 24, 2023 8:33 pm
Sounds to me like the intention is to eliminate some ring and cylinder wall contact area to reduce friction.
Yes, that was my motivation but, it could also effect a tension a little.
Re: Cast Iron Ring Mods
Posted: Thu Feb 09, 2023 12:32 pm
by jed
You can back cut the ring to relieve some tension.