Lubrication System Components
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| Illustration 1 | g00738455 |
(1) Engine oil filler (2) Engine oil level gauge (3) Engine oil cooler (4) Bonnet (6) Bypass valve for the engine oil filter and for the engine oil cooler (7) Engine oil filter (8) Engine oil pan (9) Drain plug | |
Oil Flow through the Oil Filter and Oil Cooler
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| Illustration 2 | g00783867 |
Lubrication system schematic (1) Flow of engine oil to the main engine oil gallery (2) Bypass valve for the engine oil filter (3) Engine oil cooler (4) Bypass valve for the engine oil cooler (5) Engine oil filters (6) Engine oil pan (7) Engine oil pump | |
Engine oil pump (7) is driven by the front gear train. The engine oil pump pulls engine oil from engine oil pan (6) through a suction bell. The suction bell has a screen in order to strain large debris from the engine oil.
The engine oil pump has a relief valve that controls the pressure of the engine oil from the engine oil pump. If the engine oil pressure from the pump becomes excessive, the relief valve opens and some of the engine oil returns to the engine oil pan. This prevents high pressure engine oil from damaging the O-ring seals for the engine oil cooler and the engine oil filter.
Engine oil filters (5) and engine oil cooler (3) have bypass valves (2) and (4). When the engine is cold, the pressure forces the bypass valves open. This provides immediate lubrication to the engine when cold engine oil with high viscosity causes a restriction.
After the engine warms up, the differential pressure on the bypass valves decreases and the bypass valves close. The engine oil flows normally through the engine oil cooler and through the engine oil filter.
The bypass valves will also open if there is a restriction in the engine oil cooler or in the engine oil filter. This allows the engine to be lubricated if the engine oil cooler is plugged or if the engine oil filter is dirty.
The engine oil is filtered and cooled. Clean engine oil is pumped to main engine oil gallery (1) .
Oil Flow in the Engine
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| Illustration 3 | g00820739 |
Schematic of the flow of engine oil through the engine (1) These openings are plugged. (2) Supply for the turbocharger (3) Supply for the governor drive (4) Rocker arm shaft (5) Supply for the rocker arm shaft (6) Supply for the rocker arm shaft and valve lifters (7) Camshaft bearing (8) Piston cooling jet (9) Supply for the timing gear (10) Supply for the front idler gear (11) Supply for the auxiliary water pump (12) Supply from the engine oil cooler to the main engine oil galleries (13) Main bearings | |
Engine oil is supplied to the main engine oil gallery in the right side of the engine. The engine oil from the right side is pumped to auxiliary water pump (11), to front idler gear (10), and to the main engine oil gallery in the left side of the engine.
After auxiliary water pump (11) and front idler gear (10) are lubricated, the engine oil drains back into the engine oil pan.
The supply of engine oil for turbocharger (2) is delivered by the main engine oil gallery in the left side near the rear of the engine. After the turbocharger is lubricated, the engine oil returns to the engine oil pan.
The supply of engine oil for timing gear (9) is delivered by the main engine oil gallery in the left side at the front of the engine.
Engine oil from the main oil galleries in both sides is supplied to main bearings (13) through drilled passages. Drilled holes in the crankshaft supply engine oil from the main bearings to the connecting rod bearings.
Engine oil from the main oil galleries is supplied to camshaft oil galleries at the front and at the rear of the engine. Drilled passages deliver engine oil to camshaft bearings (7). The engine oil circulates around each camshaft journal. The engine oil then flows to governor drive (3) and to rocker arm shaft (4). Some of the engine oil lubricates the valve stems. The remainder of the engine oil drains from the cylinder head in order to lubricate the pushrods and the valve lifters.
Engine oil from the main engine oil galleries in both sides of the engine is directed to piston cooling jets (8). The piston cooling jets are located in the engine block below each piston. The piston cooling jets provide lubrication and cooling to the components of the piston and to the cylinder wall. Each piston cooling jet has two tubes. One of the tubes provides engine oil to the underside of the piston crown. The other tube directs engine oil into a cast gallery in the piston. This gallery provides engine oil to a manifold behind the ring band of the piston. This helps cool the piston crown.
After the oil has completed lubrication, the engine oil returns to the engine oil pan.