If you look at the front of the engine under the timing cover, you’ll find a tooth belt in some cases (although in most current vehicles, this belt is replaced by a chain). It’s attached to the crankshaft and camshaft via several pulleys. Also called a gilmer drive belt many years ago, the timing belt has two jobs. It powers the engine’s camshaft and keeps it exactly in sync with the crankshaft. This ensures that the valves open and close at the right time. That’s why it’s called a timing belt. It times the valvetrain.