Camshaft specifications vary according to the performance requirements of individual internal combustion engines. Specifications vary widely, depending on the nature of the vehicle or equipment to which an engine provides power.
Camshafts draw power from the crankshaft via a timing chain or timing belt to operate an internal combustion engine's intake and exhaust valves, with oblong-shaped lobes that move a valve stem each rotation. A camshaft's two primary specifications are its duration and its lift.
Duration determines how long a valve remains open during an engine cycle, and lift determines how far a valve opens. Changes in these specifications optimize an engine for either torque or horsepower. The number of valves varies by engine; thus, the number of camshaft lobes likewise varies.
Performance parts dealer Jegs advises taking performance and engine configuration into consideration when purchasing a camshaft, and aftermarket parts manufacturer Edelbrock lists its camshafts by desired performance.