What are valve springs used to do in a cylinder head?

• A. Open valves
• B. Close valves
• C. Set valve timing
• D. Lubricate valve stems

Answer: (B)

Valve springs pull the valves back to their closed position after the camshaft opens them. When a valve is lifted by the cam, the spring compresses; when the cam lobe moves away, the spring’s tension drives the valve down to seal against its seat, shutting off the combustion chamber. This sealing is essential for maintaining proper compression and engine efficiency. The springs also help prevent valve float at higher RPMs by keeping the valve in contact with the cam follower. Opening the valves, setting valve timing, and lubricating valve stems are handled by the camshaft/rocker system and the engine oiling system, not by the springs. So the primary job of valve springs is to close the valves.