Topic summary
Dual overhead cam
Extracted from the Wikipedia article Overhead camshaft engine.
Dual overhead camshaft (DOHC)
A dual overhead cam, double overhead cam, or twin-cam engine has two camshafts over each bank of the cylinder head, one for the intake valves and another for the exhaust valves. Therefore there are two camshafts for a straight engine and a total of four camshafts for a V engine or a flat engine.