What causes a valve to burn?
Intake and exhaust valves are the final component in the valve train system. They are made of hardened metal that must withstand the extreme conditions of the combustion chamber. Intake and exhaust valves are responsible for controlling the flow of gases through the combustion chamber. Intake valves let air in, whereas exhaust valves let air out. They are shaped to have a slim stem leading to a flatter face, with the intake valves often being larger than the exhaust. Each valve is designed to only move up and down, not side to side. When a valve is closed, it sits tightly on the valve seat to stop the flow of air. But when it is open, it separates from the valve seat to allow air to flow through. In many modern engines, each cylinder has two intake and two exhaust valves per cylinder.
