Timing Chain & Belts
All current automobile piston engines have a camshaft and a crankshaft. The crankshaft
transmits the power from the pistons as they move up and down and changes it to a rotating
motion. ( This is like the pedals on a bicycle changing the up and down motion of your legs to a
rotating motion. ) Th e crankshaft drives the CAMSHAFT, which opens and closes the valves in
the engine. A camshaft has eccentric LOBES or CAMS all in a row: one lobe for each valve.
This lobe presses on a cam follower or valve lifter which opens the valve.
For each cylinder, the camshaft first opens the intake valve to let in fuel and air to be burned.
After this, the camshaft opens the exhaust valve to release the burned fuel gasses, which pass
out the exhaust pipe. This all must happen at exactly the right time. This coordination of the
crankshaft with the opening and closing of the valves via the camshaft is called Valve Timing
or Camshaft Timing.
If valve timing is incorrect a valve can open at the wrong time and bend the valve!!