BOLT AS 4883971 - Caterpillar

Illustration 3 g01139792
Turbocharger With Wastegate
(12) Actuating lever
(13) Canister
(14) Line (boost pressure) When the engine is operating under conditions of low boost, a spring pushes on a diaphragm in canister (13). This action moves actuating lever (12) in order to close the valve of the wastegate. Closing the valve of the wastegate allows the turbocharger to operate at maximum performance.As the boost pressure through line (14) increases against the diaphragm in canister (13), the valve of the wastegate is opened. When the valve of the wastegate is opened, the rpm of the turbocharger is limited by bypassing a portion of the exhaust gases. The exhaust gases are routed through the wastegate which bypasses the turbine wheel of the turbocharger.Note: The turbocharger with a wastegate is preset at the factory and no adjustment can be made.Bearings (4) and (6) for the turbocharger use engine oil under pressure for lubrication. The oil comes in through oil inlet port (5). The oil then goes through passages in the center section in order to lubricate the bearings. Oil from the turbocharger goes out through oil outlet port (10) in the bottom of the center section. The oil then goes back to the engine lubrication system.Valve System Components
Illustration 4 g01107026
Valve system components
(1) Rocker arms
(2) Bridge
(3) Spring
(4) Pushrods
(5) Exhaust valve
(6) Inlet valves
(7) Lifter
(8) Camshaft lobe The valve system components control the flow of inlet air into the cylinders during engine operation. The valve system components also control the flow of exhaust gases out of the cylinders during engine operation.The crankshaft gear drives the camshaft gear through an idler gear. The camshaft must be timed to the crankshaft in order to get the correct relation between the piston movement and the valve movement.The camshaft has two camshaft lobes for each cylinder. The lobes operate the inlet and exhaust valves. As the camshaft turns, lobes on the camshaft cause lifters (7) to move pushrods (4) up and down. Upward movement of the pushrods against rocker arms (1) results in downward movement (opening) of valves (5) and (6).Each cylinder has two inlet valves and one exhaust valve. Valve springs (3) close the valves when the lifters move down.Air Inlet Heater
The engines are equipped with an electric heater that is located behind the air inlet elbow. The electric heater has two functions:
Aid in starting
Aid in white smoke cleanup during start-upUnder the proper conditions, the Electronic Control Module (ECM) turns on the electric heater. The following conditions are evaluated prior to activating the electric heater:
Jacket water coolant temperature
Inlet manifold air temperature
Ignition switch position
Duration of timeThe system is capable of delivering heat for 30 seconds prior to start-up and during cranking of the engine. After the engine has started, the system is capable of delivering heat constantly for 7 minutes, or the system can cycle the heat for 13 minutes. During the heating cycle, the heat is on for ten seconds and the heat is off for ten seconds.If the air inlet heater malfunctions, the engine will still start and the engine will