3208 – Lubrication System

Schematic Of Lubrication System
(1) Vacuum pump or air compressor. (2) Cylinder head. (3) Front cover for the engine. (4) Oil passage (to turbocharger). (5) Oil manifold. (6) Piston cooling jet. (7) Oil pump bypass valve. (8) Base for the oil cooler. (9) Oil cooler. (10) Oil pump. (11) Cover for oil pump. (12) Suction bell for oil pump. (13) Oil cooler bypass valve. (14) Oil cooler bypass valve. (15) Oil filters.

The lubrication system uses a six lobe, rotor type oil pump (10). Bolts hold the cover for the oil pump (11) on the front cover for the engine (3). The gear on the crankshaft drives the outer rotor. The outer rotor has rotation in a bearing in the front cover for the engine.

The inner rotor goes on a short shaft in the front cover for the engine. The inner rotor is driven by the outer rotor.

Oil pump bypass valve (7), in the cover for the oil pump (11) controls the pressure of the oil coming from oil pump (10). The oil pump can put more oil into the system than needed. When the pressure of the oil going into the engine is more than 380 to 550 kPa (55 to 80 psi) the oil pump bypass valve (7) will open. This permits the oil that is not needed to bypass the system.

Oil from the oil pan is pulled through the suction bell for the oil pump (12) by oil pump (10). The oil is sent by the oil pump to an oil passage in the front cover for the engine (3). Oil from this passage goes to the cylinder block and on to the base for the oil cooler (8). The base for the oil cooler is on the left side of the engine, near the front of the engine. Oil cooler bypass valve (13) in the base for the oil cooler, will let the oil go around the oil cooler (9) when the oil is cold or if the restriction in the oil cooler is more than the other parts of the system. A difference in pressure of 85 to 105 kPa (12 to 15 psi) between the oil inlet and the oil outlet will open the bypass valve.

Oil from the oil cooler goes to the oil filters. Bypass valve (14) in the base for the oil cooler will let oil go around oil filters (15) if there is a restriction in the oil filters.

There are two pressure outlets in the base for the oil cooler. The pressure outlets are on the outlet side of the oil cooler and oil filters. The pressure outlets are for the sending unit and switch for the oil pressure.

Oil from the oil filters (15) goes through a passage in the cylinder block to oil manifold (5). The oil manifold is in the center of the cylinder block, above the camshaft, and goes the full length of the cylinder block. Oil goes from the oil manifold to the bearings for the camshaft. There are grooves in the bores in the cylinder block around the bearings for the camshaft. The bearing surfaces (journals) on the camshaft get lubrication from these grooves through a hole in the bearings for the camshaft.

Some of the oil goes around the grooves and down through passages to the main bearing bores. The main bearing bores in the cylinder block have grooves to let oil go to piston cooling jets (6) that spray oil to cool the pistons and lubricate the piston pin. The remaining oil goes through a hole in the upper main bearing and into a groove in the bearing. This oil gives lubrication to the bearing surfaces (journals) of the crankshaft for the main bearings.

Oil gets into the crankshaft through holes in the bearing surfaces (journals) for the main bearings. Passages connect each bearing surface (journal) for the main bearing with the bearing surface (journal) for the connecting rod next to it.

Crankshaft Oil Schematic

NOTE: No. 1 main bearing surface (journal) does not have an oil passage to a connecting rod bearing surface (journal).

Oil passage (4) from the rear of oil manifold (5) goes up to the center housing of the turbocharger for lubrication of the bearings. Oil from the turbocharger drains back to the cylinder block and down to the oil pan.

Oil for the rocker arms comes from the oil manifold (5) through passages in the cylinder block. The passages in the cylinder block are in alignment with a passage in each cylinder head. The passage to the cylinder head on the left side is near the front of the cylinder block. The passage to the cylinder head on the right side is near the rear of the cylinder block.

The passage in each cylinder head sends the oil into an oil hole in the bottom of the mounting surface of the bracket that holds the shaft for the rocker arms. The oil hole is in the front bracket on the left side and in the rear bracket on the right side. The oil then goes up through the bracket and into the center of the shaft for the rocker arms. Oil goes along the center of the shaft to the bearings for the rocker arms. From the rocker arms, the oil is pushed through small holes to give lubrication to the valves, push rods, camshaft lifters, and camshaft lobes.

After the lubrication oil has done its work, it will return to the oil pan for the engine.

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