Which statement best describes a crankshaft?

• A. A shaft used to operate cam lobes.
• B. A shaft that drives timing gears.
• C. A shaft constructed with cranks (throws), one for each piston.
• D. A shaft that cools the engine.

Answer: (C)

The main idea is that the crankshaft is the part that turns the pistons’ up-and-down motion into rotational motion for the engine. It is built with cranks (throws), one for each piston, offset from the central axis. The connecting rods attach to these throws, so as each piston moves, the offset causes the crankshaft to rotate. This arrangement provides the necessary multi-cylinder geometry and power transfer along the shaft. Other components described belong to different systems: the camshaft has the lobes that operate valves; timing gears are driven by the crank through the timing mechanism; cooling is handled by the water pump and radiator, not the crankshaft itself.