Double overhead cam definition
(DOHC) An engine with two camshafts located above the cylinders . One drives the intake valves and the other operates the exhaust valve . In a single overhead cam engine (SOHC), one cam has enough lobes to drive both the intake and exhaust valves . The DOHC engine is considered to be a very sophisticated and more efficient engine; but is sometimes more difficult to adjust the valves. See engine type .