What is cylinder head skimming?

Answer 1

Skimming is another term for plaining or machining. The head is placed in a milling machine that cuts a slight amount off the part of the head that makes contact with the engine block. This will increase the compression ratio of the engine and may require that you start using premium high octane fuel. This will increase the horsepower of the engine slightly. This process if sometimes used to straighten a head that has been warped due to overheating.