An engine design that places the camshaft directly above the valves in the cylinder head, rather than in the engine block. This eliminates the need for pushrods, reducing the moving mass of the valvetrain. The design allows for higher engine speeds and more precise valve timing control.
Heard on the job
The timing belt snapped on that overhead cam four-cylinder, so the pistons definitely hit the valves.
Also heard as
- OHC
Do not mix it up with
- Overhead valve: Overhead valve (OHV) engines have valves in the head but the camshaft in the block, whereas overhead cam (OHC) engines put the camshaft in the head.
Related terms
Overhead valve
An engine design where the intake and exhaust valves sit in the cylinder head above the combustion chamber.
Pushrod
A metal rod that transfers motion from the camshaft to the rocker arms in overhead valve engines.
Timing belt
A reinforced rubber belt that synchronizes the rotation of the crankshaft and the camshafts.