A camshaft is a rod featuring a series of protruding cams, designed to transform rotary motion into linear motion. In the case of an engine, a camshaft is a part of the engine that regulates the opening and closing of an IC engine's inlet and exhaust valves. A camshaft has more than one cam. It has many radial cams, which displace the inlet or outlet valve. This cam slides over the inlet and exhaust valves.