970973 Volvo.Penta Hexagon screw

Illustration 1 g01020802
Flow diagram of the lubrication system (1) Piston cooling jets (2) Rocker arm shaft (3) Camshaft (4) Main oil gallery (5) Engine oil cooler (6) Idler gear (7) Engine oil relief valve (8) Crankshaft (9) Engine oil pump (10) Engine oil filter (11) Engine oil pan (12) Engine oil bypass valve (13) External line (supply) (14) TurbochargerPressure for the lubrication system is supplied by an engine oil pump (9). The gerotor type pump has an inner rotor and an outer rotor. The axis of rotation of the rotors are off-center relative to each other.The inner rotor has four lobes which mesh with the five lobes of the outer rotor. When the pump 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.Lubricating oil from engine oil pan (11) flows through a strainer and a pipe to the suction side of the engine oil pump. The lubricating oil flows from the outlet side of the pump through a passage to engine oil filter (10) .The oil then flows from the filter head through a pipe to engine oil cooler (5). The plate type oil cooler is located on the left side of the cylinder block. From the engine oil cooler, the oil then flows to main oil gallery (4) that is located along the left side of the cylinder block.Lubricating oil from the main oil gallery flows through high pressure passages to the main bearings of crankshaft (8). The oil then flows through the passages in the crankshaft to the connecting rod bearing journals.The pistons and the cylinder bores are lubricated by the splash of oil from piston cooling jets (1), which are connected to the main oil gallery.Lubricating oil from the main oil gallery flows through passages in the cylinder block to the journals of camshaft (3). The oil then flows from the camshaft at a reduced pressure to the cylinder head. The oil flows into rocker arm shaft (2) at a reduced pressure to the bearings of the rocker arm levers. The valve stems, the valve springs and the valve lifters are lubricated by the splash and the oil mist.The hub of idler gear (6) is lubricated by oil from the main oil gallery. The timing gears are lubricated by the splash from the oil.Turbochargers (14) are lubricated by oil from a connection on the left side of the cylinder block. An external line (13) that is connected from the main oil gallery supplies oil to the top of the turbocharger. The oil then flows through the turbocharger. An external line that is connected to the bottom of the turbocharger returns the oil to the engine oil pan.Engine oil relief valve (7) is installed in order to prevent damage to the lubricating system. The engine oil relief valve helps keep a constant oil pressure throughout the engine. If the main system relief valve fails to open, the high engine oil pressure can cause damage to engine components. In order to limit the possibility of engine damage due to a malfunctioning relief valve, the lubrication system contains a backup system for engine oil relief valve (7). Engine oil bypass valve (12) is located inside engine oil pan (11) on the bottom of the cylinder block.