4804591 Volvo.Penta Cylinder block

Illustration 1 g00658140
Engine oil flow of the lubrication system
(1) Reduced oil pressure
(2) Splash lubrication
(3) Full oil pressure
(4) Coolant lines
(5) Engine oil pump
(6) Suction line
(7) Engine oil cooler (if equipped)
(8) Engine oil filter Pressure for the lubrication system is supplied by a gerotor type pump (5) for engine oil. The engine oil pump is driven through an idler gear from the crankshaft gear. The engine oil pump has an inner rotor and an outer rotor. The axes of rotation of the rotors are off-center relative to each other. There is a key between the inner rotor and the drive shaft. The inner rotor has six lobes that mesh with the seven lobes of the outer rotor. When the inner lobe rotates, the distance increases between the lobes of the outer rotor and the lobes of the inner rotor in order to create suction. When the distance decreases between the lobes, pressure is created. Engine oil from the engine oil pan flows through a strainer and suction line (6) into the inlet of the engine oil pump. The engine oil flows from the outlet side of the engine oil pump through a line to an oil pressure relief valve. The oil pressure relief valve is installed near the bottom of the left side of the cylinder block. The oil pressure relief valve on the engine oil pump opens if the engine oil pressure is too high. The engine oil is returned to the engine oil pan after the engine oil flows through the oil pressure relief valve. If the engine is equipped with an engine oil cooler (7), the engine oil will flow from the oil pressure relief valve of the engine oil pump to the engine oil filter. The engine oil flows through the engine oil cooler. The engine oil cooler is cooled by the water/antifreeze coolant that flows through coolant lines (4).Engine oil cooler (7) and engine oil filter (8) are installed on the left side of the cylinder block.The engine oil flows from the engine oil filter through a passage drilled across the cylinder block to the engine oil gallery. The oil gallery is drilled through the total length of the left side of the cylinder block.Engine oil flows from the engine oil gallery through oil passages at full oil pressure (3) to the main bearings of the crankshaft. The engine oil then flows through passages in the crankshaft to the large end bearings of the connecting rod. The pistons and the cylinder bores are lubricated by splash lubrication (2) and the mist of the engine oil.Engine oil flows from the main bearings to the camshaft bearings through oil passages in the cylinder block. The engine oil flows from the center camshaft bearing journal through an oil passage in the cylinder block. The engine oil flows through the passage in the cylinder block to the cylinder head. The engine oil then flows into the rocker arm shaft at a reduced oil pressure (1) to the rocker arm levers. The valve stems, the valve springs and the valve lifters are lubricated by splash lubrication (2) and the mist of the engine oil.The hub of the idler gear is lubricated by engine oil from the engine oil gallery. The timing gears are lubricated by the engine oil with splash lubrication (2).The piston cooling jet is connected to the engine oil gallery. The piston cooling jet sprays engine oil on the underside of the No. 1 piston in order to cool the piston.