All models of BMW since 1993, all models of Cadillac, the Chevrolet Corvette, the Chrysler Neon and PT Cruiser, and all models of Mercedes except the 2012 A Class 1,461 cubic centimeter and Citan van have timing chains instead of belts. Nearly 40 brands of cars use timing chains for a portion of their models.
The majority of cars on the road have four-stroke engines. During one complete cycle, the crankshaft rotates twice, and the camshaft or camshafts spin once. The relationship between the rotation of the camshaft and crankshaft is called mechanical timing. Without proper mechanical timing, the engine cannot work, as the valves need to open exactly when the pistons are firing. A timing belt or chain is the device that connects the crankshaft to the camshaft.
In the mid-1960s, Pontiac developed an overhead cam and claimed to be the first American car with a rubber timing belt. Before 1966, when Pontiac revealed this engine design, nearly every four-stroke engine used a timing chain. Rubber timing belts are often made with fiberglass or Kevlar woven into them for strength, and they are known to be quiet as they rotate. Rubber belts wear out over time and must be regularly replaced, whereas timing chains typically last much longer.
