Timing System The timing belt is meshed with the sprockets, the crankshaft sprocket becomes the drive sprocket, and thus functions to drive the camshaft and oil pump. Timing belt The timing belt is the cogged type, using rubber as its basic material, and it employs a high-strength glass fiber core which does not expand or contract. The features of the cogged-type belt compared to a chin are no expansion/contraction, low noise level, no necessity for lubrication, light weight, etc. G424 Service Manual Engine System 25