Valve Seats

Valve seats are a critical engine component because they are the foundation of the valve train. The seats provide a surface for the valves to seal against when they close so there’s no loss of compression or pressure from the combustion chamber. The seats also help cool the valves by conducting heat away from the valves into the cylinder head. The seats also support the valves and determine installed valve height, which affects valvetrain geometry and valve lash. The diameter of the seats and the contour of the angles machined into the seats’ faces also limit how much air the engine can flow at any given valve lift and rpm. Because of all these factors, the valve seats deserve much attention whether rebuilding a stock engine or building a performance engine.