If the camshaft is the “brain,” the valves and rocker arms are the “hands” that physically open and close the engine’s airways. This system must operate with microscopic precision while being hammered thousands of times per minute.

• Head & Face: The flat, circular part that seals against the “valve seat” in the cylinder head.

• Stem: The long rod that slides up and down through a Valve Guide.

• Materials: * Intake valves stay relatively cool because of the incoming air.

• Exhaust valves are often made of Stellite or are Sodium-filled. The liquid sodium inside the hollow stem sloshes back and forth to pull heat away from the valve head, preventing it from melting.

• Valve Springs: These are critical. The camshaft pushes the valve open, but the spring is what pulls it shut. If the spring is too weak, “valve float” occurs at high RPM, and the engine loses power.