What does DOHC, SOHC and OHV mean?

OHV, or Overhead Valve

The camshaft, which is located in the engine block, houses the valves that allow the air-fuel mixture into and out of the cylinders. Pushrods are activated by the camshaft and move up and down to open or close valves within the engine block.

OHV engines can also be called pushrod engines. However, they cannot produce the same torque at low engine speeds as the overhead-camshaft engine.

They were extensively used by domestic manufacturers for many years. Today, OHV engines such as the GM's 5.3 liters V-8s or the Stellantis 5.7 liter V-8s, and the GM's 6.2 liters V-8s, are primarily used for large pickup trucks and SUVs. They are also used in performance models like the Dodge Challenger SRT or Chevrolet Corvette.

SOHC or Single Overhead Camshaft

The camshaft is located in the cylinder head, above the valves. The valves and rocker arms are controlled by the camshaft. An OHC engine can have one camshaft that opens and closes both the intake and exhaust valves.

SOHC engines are generally more powerful than OHV engines. A smaller SOHC engine may produce more horsepower than an OOH engine and provide better fuel economy. But, SOHC engines aren't as torque-producing at low speeds as OHV engines.

DOHC or Dual Overhead Camshaft

DOHC engines are the dominant type today. They are the most efficient engines and produce the highest horsepower per liter. Dual camshafts control the intake and exhaust valves. Horizontally opposed V-type engines will have four camshafts, with two for each cylinder bank.

DOHC engines can have four valves per piston, instead of just two. This increases airflow, power, and efficiency. DOHC engines are more complicated and therefore more expensive to build.

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