Ring Replacement - OS 40 FS

Guys,
I got a swap meet OS 40 FS (not surpass) which cleaned up real good. I'm thinking of replacing the piston ring with one from Frank Bowman. Is there anything I should do to the cylinder, etc?

Thanks

No one else has jumped in on this one, so I will.

First off, why are you replacing the ring? If you have good compression and it is a good runner, just leave it.

If you feel you should (or want to) replace the ring, check everything over when you disassemble the engine. On a used ringed engine it is not good to take it apart without replacing the ring as you could lose the ring seal. So I wouldn't recommend taking it apart unless there were a problem and you wished to replace the ring.

If the cylinder is smooth from running, but the piston and cylinder otherwise looks good, you might want to hone it just slightly. If you have an iron cylinder, it is usually no problem to hone it. If it is a chrome plated cylinder, depending on the hardness, you may or may not be able to (or need to). If it is nickel plated, you need to be careful that you do not strip the plating or scratch through it. In this case you may be better off leaving it alone.

There are a lot of "ifs" here, I know, but that is the nature of the game. I took my car into a shop in Cincinatti while we were on a trip to get the spark plugs replaced. They ended up wanting to do over $500 worth of work to the car ("It needs this and that, and then you should....") I settled for spark plugs, only. It was misfiring and they were getting old. That solved the problem.

Sometimes doing too much is not a good thing.

Leonard's advise makes sense to me. I'm not fond of ringed engines as setting the end gap is a detail the factories seldom seem to get right. But IF I had a "not a Surpass", I would get with some OS parts lists and see if it is possible to update the critter into a Surpass. If you could swap out the cam and head, you would be a much happier camper, as the power difference is supposed to be significant. Bob Zambelli's 4s forum at Windy's website may be your best bet for info on this. Steve

Thanks Leonard and Steve. I took a closer look at it and here's what I did. The ring was very shiny in some areas, while the rest looked like a ring (kinda dull grey). The ring was stuck in the piston. This engine was run with castor oil which had caused the ring to stick...at least this is what I think. After removing the ring and cleaning out the ring groove I cleaned the ring and then used some very fine sandpaper I went all over the ring to "dull" it back up. I used a "ScotchBrite" pad and oil to swish out the cylinder. There weren't any scores or scratches so I figured I just clean out any "varnish" and clean the cylinder up. I did put the ring in the cylinder to check the end gap and it looked good. I didn't measure it but it looked like a few thousanths. After I reassembled the engine I ran it up on the run up stand real rich for a few tanks. I then ran 24 more oz through it taking it up to full throttle and leaned it out and back it down 300 RPM. The compression is very good!
I did all this because I saw Jim Schuett in Milwaulkee and Chicago fly his Twister with a standard OS 40 FS and it did real well. I had bought this engine early this year at a swap meet pretty cheap, so I thought, "why not"? So I pulled the Banshee off the wall and wacked the nose down to what I think it will take to balance. I'm in the middle of refinishing the fuse and I'll keep everybody posted how this project works out.