Which component allows changing the cam timing to three or nine different positions?

• A. Lifter
• B. Timing Chain
• C. Multi-keyway Crankshaft Gear
• D. Pushrod

Answer: (C)

Changing cam timing in a way that lets you pick from several discrete positions is done by selecting a different alignment between the crankshaft and camshaft using a gear that has multiple keyways. A multi-keyway crankshaft gear provides several keyed positions, so you can rotate the gear to place the cam in one of several fixed phase relationships to the crank. That lets the engine run with different cam timing settings, such as three or nine possible positions, depending on the design.

The other parts don’t enable this kind of selectable timing. The lifter is just part of the valve-train that translates cam lobe motion into valve movement, not timing adjustment. The timing chain maintains the correct relationship between the gears but doesn’t by itself offer multiple discrete timing positions. The pushrod is also part of the valve-train path and has no role in changing cam timing.