Which component directly opens and closes the valves as the camshaft rotates?

• A. Pushrod
• B. Lifter
• C. Camshaft
• D. Timing Chain

Answer: (C)

The camshaft provides the timing and lift that governs valve motion. As it rotates, each cam lobe has a raised profile that pushes a follower (lifter) upward. That movement is transmitted through the valve train—often via pushrods and rocker arms—to lift the valve stem and open the valve. When the lobe rotates away, the follower returns and the valve spring closes the valve. The timing chain (or belt) simply keeps the camshaft synchronized with the crankshaft; it doesn’t open the valves. The pushrod and lifter are intermediary parts, but the action of opening the valve comes from the camshaft’s lobes driving the valve train.