The Functions of the Exhaust Valve: Size, Lift and Timing in Relation to Engine Displacement and Speed

EVEN a superficial examination of the size, lift and timing of the exhaust valves of a number of engines suggests that this important member is rather a Cinderella, and has in many cases received scant attention. It is true that special steels have been produced and copper‐cored or salt‐cooled valves employed to prevent burning and pitting, but the dimensions and timing show a lack of agreement which is only to be accounted for by assuming that tradition and a misplaced confidence in the “mechanical instinct” have often been the only guide.