PLATE AS-PRESSURE 3N8125 - Caterpillar

The valve system components control the flow of the inlet air and the exhaust gases into the cylinders and out of the cylinders during engine operation.The crankshaft gear drives the camshaft gears through idlers. Both camshafts must be timed to the crankshaft in order to get the correct relation between the piston and the valve movement.The camshafts have three lobes for each cylinder. Two lobes operate the valves and one operates the fuel injector.
Illustration 1 g01042301
Valve system components
(1) Rocker arm
(2) Bridge
(3) Rotocoil
(4) Valve spring
(5) Pushrod
(6) Lifter As each camshaft turns, the lobes on the camshaft cause lifters (6) to move up and down. This movement causes pushrods (5) to move rocker arms (1). The movement of the rocker arms cause bridges (2) to move downward. The bridges open two valves simultaneously. The valves can be either inlet valves or exhaust valves. There are two inlet valves and two exhaust valves for each cylinder.Valve springs (4) cause the valves to close when the lifters move downward.Rotocoils (3) cause the valves to turn while the engine is running. The rotation of the valves keeps the carbon deposits on the valves to a minimum which gives the valves a longer service life.