Broken Piston Ring question
 

I was given a small twin cylinder gaso engine...no idea of the manufacturer...looks to be about a 40cc, but haven't measured it. In inspecting the engine, which appears to have never been run, I see that it has 2 piston rings per cylinder...the lower ring of 1 cylinder is broken. Assuming (yes, I know) everything else is OK mechanically, what would be the impact on performance by removing the broken ring from that cylinder and removing the good one from the other...It seems to me that the single ring configuration is more common in small engines that double rings...thoughts?
Thanks
M

Most guys that run gas engines that have twin ringed Pistons would often remove both stock rings and install a high quality reproduction ring and just run a single ring. Running with a single ring of better quality than stock will yield a bit better ring seal and also reduce friction.

I dont run gas model engines, but I've read a lot about them. I'd not hesitate to run a single ring in a twin ringed piston.

I have a twin ring chainsaw with just the top ring. Been that way a few years. Runs just fine.

Thanks for the info...I'll put it on my test stand and see how it runs...Don't know anything about the engine, measured the bore and stroke and it appears to be about 60CC. It will either run or come apart...hope it's the former rather than the latter!
M

Murphey , I used to run a few old Horner twin engines that were 60 cc . The only way you could get good power and easy hand starting was to remove the bottom ring . The engine was too tight with the second ring in place .After removing the lower rings It picked up about 300 rpm and was able to start it with out an electric starter .

Make sure to remove the broken ring before you run it. Best to have one ring in top ring groove.

Best Regards, John West Mich

When you put the good ring back in make sure the ring gap is NOT on the exhaust port side. You don't want to clip your ring and break that one.

Some engines have a tiny pin in ring grove so the Piston ring does not rotate & catch ports. John