Timing belt (Timing belt) is an important part of the engine distribution system, through the connection with the crankshaft and with a certain transmission ratio to ensure the accuracy of the inlet and exhaust time. The use of belt rather than gear to drive is because the belt noise is low, the transmission is accurate, the amount of its own change is small and easy to compensate. Obviously, the life of the belt must be shorter than that of the metal gear, so the belt should be replaced regularly. The role of the timing belt is to correct the stroke of the piston (up and down movement) when the engine is running, the opening and closing of the valve (time), adjust the order of ignition (time), and maintain "synchronous" operation at all times under the connection of "timing". Timing is through the timing mechanism of the engine, so that each cylinder is just done: when the piston is right up to the top dead center, the valve is just closed, and the spark plug is just ignited. The timing belt is a wear and tear, and once the timing belt breaks, the camshaft will not operate according to the timing, which is likely to cause serious damage to the valve and piston impact, so the timing belt must be replaced according to the mileage or time specified by the original factory.