CONNECTING ROD AND PISTON GROUP 9L8568 - Caterpillar

valves to close. Normal oil flow will resume through the oil cooler (3) and the oil filters (7) .The bypass valves will also open when there is a restriction in the oil cooler or the oil filter. This prevents a restricted oil filter or a restricted oil cooler from stopping the lubrication of the engine.There is also a bypass valve in the engine oil pump (5). This bypass valve controls the pressure of the oil from the oil pump. The capacity of the oil pump exceeds the amount of oil that is needed to lubricate the system. The oil pressure will increase because of the excessive oil. This will cause the bypass valve to open. This will allow the oil that is not needed to go back to the inlet oil passage of the oil pump.Oil Flow In The 3408C Engine
Illustration 2 g00320189
Schematic Of Oil Flow In The 3408C Engine (1) The flow to the air compressor. (2) The flow to the rear idler gear. (3) The flow to the rocker arm shaft. (4) The flow to the power take-off. (5) The flow to the fuel injection pump housing. (6) Rocker arm shaft. (7) The flow to the rocker arm shaft and the valve lifters. (8) The flow to the valve lifters. (9) Bore for the camshaft bearings. (10) Piston cooling jets. (11) The flow to the turbocharger. (12) Left side oil manifold. (13) The flow to the timing gear housing. (14) The flow to the front idler gear. (15) The oil supply line to the manifold in the cylinder block. (16) Right side oil manifold. (17) The main bearing bores.
Illustration 3 g00331845
3408C Lubrication System Components (20) Bypass valve for the oil cooler. (21) Bypass valve for the oil filters. (22) Oil cooler. (23) Oil inlet to the cooler. (24) Oil outlet from the cooler (inlet to filters). (25) Oil filters. (26) Oil pan.The oil manifolds are cast into the sides of the cylinder block. Oil flows into the right oil manifold (16) from the bypass valve body. The oil flows from the right oil manifold (16) to the left oil manifold (12) through drilled passages in the cylinder block. These drilled passages in the cylinder block connect to the main bearing bores (17) and the camshaft bearing bores (9). The bearings are lubricated by the oil that comes from the bearings. Oil from the main bearings flows through holes that are drilled in the crankshaft. This oil lubricates the connecting rod bearings. A small amount of oil flows through the piston cooling jets (10). This oil cools the piston.Oil goes through grooves in the outside of the front and rear camshaft bearings to passage (7) and to passage (8). This oil lubricates the valve lifters and the rocker arm shafts. Holes in the rocker arm shafts allow the oil to lubricate the valve system components in the cylinder head.The fuel injection pumps and the governor receive oil from passage (5) in the cylinder block. Oil for the hydraulic operation