-Driving with a defective timing chain can cause severe engine damage and is also dangerous because your vehicle can stop suddenly without warning. -A timing chain is made of metal, much like a bicycle chain. A timing chain runs inside the engine because it needs to be lubricated by the engine oil. -The timing chain is an important component of the engine. When it fails, the damage can be catastrophic, resulting in bent valves, damaged pistons, and in some cases, total engine failure. However, regular maintenance and care can help the timing chain last the life of the vehicle.