The gear is not worn, but pitted. The tooth shape is fine for the most part, the original gear appears to be made from a casting, and there are many pits showing in about half of the teeth.
This is a very early Rolls Royce engine, the original gear is some type of hardened steel, but I don't...
Actually, this is a very old engine and the gear will be running against a phenolic gear, not a timing chain.
If we use the 4340, how hard should it be heat treated to?
