On overhead cam engines, the camshaft is mounted directly above the valves.
As the camshaft turns, the valve lifters ride up on the lobes, opening the valves.
As the high point of the lobes pass, the lifters ride down the other side of the
lobes and the valves close. In pushrod-type engines, the camshaft is located in
the center of the engine and valve lifters ride on the lobes. Pushrods are placed
on the lifter’s seat and fitted into a rocker arm seat at the other end. As the shaft
turns, the lifters ride up and down on the lobes and push the pushrods up and
down, the rods push on the rocker arms (small see-saw type devices) that push
on the valve stems, opening and closing the valves in precise mechanical timing.
There are consequences of neglecting certain maintenance practices. And
when it comes to engines, they can be very costly.
Turbo and Super Chargers
A turbocharger is driven by exhaust gas flow to power an air compressor. The
compressor portion of the turbo draws fresh air from outside and forces it into
the air intake of the engine, increasing the engine output. Turbocharged engines
benefit greatly from using synthetic motor oil, more on this in the chapter on
lubrication.