On a four-stroke engine, if gear A is a camshaft spinning at exactly half the speed of gear B, then B is a/an

On a four-stroke engine, if gear A is a camshaft spinning at exactly half the speed of gear B, then B is a/an

• A. Piston
• B. Valve
• C. Camshaft
• D. Crankshaft

Answer: (D)

In a four-stroke engine, the camshaft must complete one rotation for every two rotations of the crankshaft so that the valves open and close in sync with the piston’s two-stroke cycle. That 2:1 relationship is what governs timing: the camshaft turns at half the crankshaft speed. If gear A (the camshaft) is spinning at half the speed of gear B, gear B must be the crankshaft. The crankshaft is the fast-moving shaft connected to the pistons, converting their up-and-down motion into rotation, while the camshaft, driven by that rotation, operates the valves with its lobes.

In a four-stroke engine, the camshaft must complete one rotation for every two rotations of the crankshaft so that the valves open and close in sync with the piston’s two-stroke cycle. That 2:1 relationship is what governs timing: the camshaft turns at half the crankshaft speed. If gear A (the camshaft) is spinning at half the speed of gear B, gear B must be the crankshaft. The crankshaft is the fast-moving shaft connected to the pistons, converting their up-and-down motion into rotation, while the camshaft, driven by that rotation, operates the valves with its lobes.