What is the purpose of valve clearance?

Valve clearance, or valve lash, is the gap between the valve stem and the rocker arm or camshaft. Its primary purpose is to ensure proper operation of the engine's valvetrain by allowing for thermal expansion of engine components as they heat up. Adequate clearance prevents valve damage and ensures that valves open and close fully, which is critical for optimal engine performance and efficiency. Insufficient clearance can lead to valve noise, poor engine performance, and potential engine damage.