I have a Craftsman/Tecumseh snowblower and the piston rings need to be replaced. Son replaced the top (stripped spark plug threads) and while doing so, went further and did a break down to clean it and discovered one of the rings had a chip. I was able to track down a NOS set in Maryland but when he was rebuilding the engine, broke one of the rings. I cannot locate a ring set anywhere. Any ideas. Worst case is a just install a new engine.