Final answer:
The camshaft in an engine moves the lifter to open cylinder valves, which in turn moves the pushrods and actuates rocker arms for valve operation.
Step-by-step explanation:
The camshaft moves the lifter (also known as tappet) to open cylinder valves in a four-stroke internal combustion engine. When the camshaft rotates, the lobes (cams) push against the lifters, which in turn move the pushrods. These pushrods actuate the rocker arms that open and close the valves at the top of the cylinder. This process allows the engine to move through its intake, compression, power, and exhaust strokes in a sequential manner.