Cam timing refers to the precise alignment of the camshaft and crankshaft in an internal combustion engine. This alignment is crucial because it determines when the engine's valves open and close in relation to the position of the pistons. Proper cam timing ensures optimal engine performance, efficiency, and power output. If the cam timing is off, it can lead to various issues, such as reduced power, poor fuel economy, and increased emissions. Adjusting the cam timing can be done through various methods, including using adjustable cam gears or modifying the timing belt or chain, depending on the engine design.