Returns a valve to the closed position.

• A. Valve Spring
• B. Valve spring keepers
• C. Valve guide
• D. Poppet valve

Answer: (A)

The returning force that closes a valve is provided by the valve spring. When the camshaft pushes the valve open, the spring compresses. As the cam lobe moves away, the stored energy in the compressed spring pushes the valve back down toward its seat, sealing the combustion chamber. The spring must be properly seated and functioning to ensure reliable closing even at high engine speeds. The valve guide simply guides the valve stem; it doesn’t force closure. The poppet valve is the component that opens and closes, but the closing action comes from the spring. The valve spring keepers just hold the spring in place; they don’t return the valve by themselves.