what do water pumps and timing belts do? and why do imports and domestics have timing chains and some have belts?

 

a water pump cycles engine coolant from your motor to your radiator

a timing chain/belt attaches on the crankshaft and the camshaft and when the crank turns it turns the cam.. thus moving the lifters, pushrods, rockerarms , and valves

why do some cars have chains and others have belts?.. im not too sure, never really thought about it..

 

most lower h/p power cars and 4cyl's have belts and most v8's have chains as well as our v6's