Both the gear attached to the camshaft and the gear on the crankshaft . They provide a means of driving the camshaft . This system is used where long life and hard service are expected as in commercial vehicles and race cars. Using gears is generally a noisier method than using a timing chain or a cog belt to drive the camshaft .
TIMING GEAR
Meaning of TIMING GEAR in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012