Touring piston oil ring "coiled wire"

[Ian Williams]

I worked on an engine fitted with cord rings, I was quite surprised to find the damage they caused was, as Tony suggests "fumonial" when compared to regular rings. This was even more sad when you learn that the engine had been built at great expense with a fresh 60+ rebore, new pistons, big valves etc only a few years previously by a professional engine builder, by the time the owner realised he had a problem and came to me the damage was done and the block was scrap. I have not used cord rings myself, whilst they may be of use in an extremely worn engine to extend its life by a few miles it would appear not a great idea in a good engine.