What is the difference between OHV, OHC, SOHC and DOHC engines?

by ZHIRONE LIANG December 06, 2022

OHV means Overhead Valve Bottom Camshaft, which means that the camshaft is arranged at the bottom of the cylinder and the valves are arranged at the top of the cylinder(OHV).

OHC means overhead camshaft, which means the camshaft is arranged at the top of the cylinder. ohc is overhead camshaft timing chain air distribution(OHC).

SOHC is single overhead camshaft air distribution. If only one camshaft at the top of the cylinder is responsible for opening and closing the intake and exhaust valves at the same time, it is called single overhead camshaft (SOHC).
DOHC is double overhead camshaft gas distribution, generally multi-valve. A cylinder with two camshafts at the top of the cylinder that are responsible for opening and closing the intake and exhaust valves is called a double overhead camshaft (DOHC).

The main difference is in the placement of the camshaft. OHV means Over Head Valve. Although almost all modern car engines have valves placed in the cylinder head, the term OHV is used to describe a pushrod engine, with the camshaft placed in the cylinder block. OHC stands for Over Head Cam, or the camshaft is installed in the cylinder head. SOHC means Single Overhead Cam, while DOHC means Double Overhead Cam.


Which one is better? It's always a heated argument. Muscle car fans will swear by an old-school pushrod, while younger car enthusiasts will say that nothing beats the twin-cam (DOHC). Each design has its pluses and minuses.

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