Which valve train component contains adjustment bolts that allow timing adjustment?

• A. Camshaft
• B. Adjustable Cam Gear
• C. Pushrod
• D. Lifter

Answer: (B)

Timing adjustment is about changing when the valves open in relation to the piston position, and the component that enables this by shifting the cam’s position is the adjustable cam gear. This gear attaches to the camshaft and is driven by the timing belt or chain from the crank. When bolts in the gear are loosened, the gear can be nudged to advance or retard the cam timing, and then the bolts are tightened to lock in the new position. That ability to fine‑tune the cam timing is what sets the valve opening to the optimal moment for engine performance or emissions.

The camshaft itself is mounted and timed through the gear and chain/belt, but it doesn’t use adjustment bolts to alter timing. The pushrod and lifter are parts of the follower path that transfers motion from the cam to the valves; they don’t provide timing adjustment.