Q: What Is a Twin-Cam Engine?

Engines that are considered twin camshaft engines will have individual separate camshafts for the exhaust and intake valves on a cylinder head instead of a single camshaft to operate both the intake and exhaust valves in a cylinder head. The twin cam engine is designated DOHC, or double overhead camshaft.

The double cams allow a cylinder head to use smaller but more valves in the head to increase airflow in and out of a cylinder. The double cam engine in some newer vehicles are using advancing and retarding devices to control the camshaft timing for the intake and exhaust valves separately. This can increase power and fuel efficiency. The camshafts can be advanced or retarded independently using oil pressure, actuators, and sensors to control them. This new style of engines with variable valve timing has enabled manufacturers to meet ever rising mileage standards. The engine horsepower and economy is increased using the DOHC versus the single overhead camshaft (SOHC) engine.