A Single Overhead Cam (SOHC) engine utilizes one camshaft located in the cylinder head to actuate both the intake and exhaust valves. This configuration is standard for the majority of Honda "D" series engines.

Technical Overview#

In an SOHC design, the camshaft is driven by the crankshaft via a timing belt or chain. As the camshaft rotates, the lobes push against rocker arms or directly against valve lifters to open the valves at precise intervals relative to the piston position.

Key Characteristics#

• Valve Actuation: A single camshaft manages the entire valve train for each cylinder.
• Complexity: Generally features fewer moving parts compared to Dual Overhead Cam (DOHC) configurations, often resulting in a more compact cylinder head design.
• Application: Predominantly found in Honda "D" series engines, though SOHC variants exist across various engine families.

Note

While SOHC engines are efficient for street applications, DOHC configurations allow for independent control of intake and exhaust valve timing, which is often preferred for high-performance tuning and VTEC optimization.

Comparison#

For information regarding engines utilizing two camshafts to actuate intake and exhaust valves independently, refer to the DOHC0 documentation.