I'm currently looking as setting up a 20hp Stanely with piston valves. My only concern is that two of the rings I have to the piston valve have significant surface rust on them. I need to know if this is going to effect the overall performance of the valve or its bore.

Rust is harder than most steel,,Are the valve liners hardend? I think it best to put in new rings,, Will they clean up with steel wool? Ben