The composition and cost of a timing belt kit can vary significantly depending on the make and model of the car engine. For engines with a toothed timing belt drive, the kit typically includes:

• The toothed timing belt itself;
• Tensioner pulley;
• Guide pulleys (one, two, or three);
• Sometimes toothed crankshaft and camshaft pulleys;
• For some engines, the kit may also include a water pump.

If the engine uses a timing chain drive, the kit may contain many more parts, such as:

• Camshaft drive chain;
• Balance shaft drive chain or oil pump drive chain;
• One or two chain tensioners;
• Chain tensioner guide shoe;
• Several chain guide rails (one to five);
• Crankshaft, camshaft, oil pump, balance shaft, or intermediate shaft sprockets;
• Necessary mounting hardware.