The crankshaft in a four-cycle engine turns at what speed in relation to the camshaft?

In a four-cycle engine, the crankshaft turns at twice the speed of the camshaft. This relationship occurs because for every two revolutions of the crankshaft, the camshaft makes one complete revolution. The motion is necessary to ensure the proper timing of the engine's valves.

The crankshaft's rotation is responsible for driving the pistons in the cylinder, while the camshaft operates the intake and exhaust valves. This design allows the engine to effectively alternate between intake and exhaust strokes, which are timed to coincide with the pistons' movements. The need for the crankshaft to turn faster ensures that the engine can produce a continuous power stroke while allowing sufficient time for the valves to open and close properly.

This fundamental relationship between the crankshaft and camshaft speeds is critical for the efficient operation of a four-cycle engine.