The valve sat in an internal combustion gasoline engine is the exterior against which the exhaust valve rests when the valve is closed.
Valve seat operationThe valve seat is a vital part of an engine in that if it is not properly placed, oriented, or formed during the building process, valve leak leakage may occur. There are typically two conical-section surfaces, one being wider while the other is a narrower cone-angle and they are machined above and below the mating plane. Once the proper width for the mating surface is formed, it can be properly seated to the mating surface of the valve and supply good sealing as well as heat transfer when the valve is closed. And when it is open it will supply good gas-flow quality via the valve.
Common issues with a faulty valve seatA faulty valve seat can cause an increase in oil consumption, an engine misfire, and a decline in engine performance.