One situated in the cylinder head, above or alongside the engine's valve gear.
An engine configuration in which the camshaft is mounted on top of the cylinder head and the camshaft is located in the cylinder block. The camshaft operates the valves via lifters and pushrods.
The camshaft operates the valves in an engine. In an overhead camshaft (ohc) engine the camshaft is above the cylinders and makes the engine more fuel-efficient than an overhead valve (ohv) engine, in which the camshaft is mounted in the engine block, further away from the valves. Most 4-cylinder cars are ohc.