Many of today's engines use timing belts, but not all. Some engines use a timing chain and sprocket arrangement. A timing belt is a precision component with teeth that mesh exactly with its mating sprockets. The uniformity of the teeth and their spacing is especially critical. The belt's teeth are precision-molded from a special rubber compound for effective mesh and longevity. The belt's inherent tensile (stretch-resistant) qualities stem from high strength cords that run parallel with the direction of belt travel.
The timing belt maintains crankshaft-to-camshaft synchronization, matching valve operation to piston position. For some engines, the belt also drives other components including the oil pump, water pump, or balance shafts.
Check your car's owner's manual for information on timing belt maintenance. Manufacturers generally recommend a certain mileage for belt replacement. If the timing belt isn't replaced during the suggested interval, the belt could break, leaving you stranded and causing major engine damage. If you're having the timing belt replaced, consider replacing other parts that may be accessed at the same time. The water pump, timing belt sprockets and tensioning pulleys are good examples. Check with a qualified service technician if you have questions about your car's needs for timing belt maintenance.