879194120 Mercruiser PUMP ASSEMBLY, Injection

oil pump is driven by an idler gear. The crankshaft gear drives the idler gear. The engine oil pump has an inner rotor and an outer rotor. The axis 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 four lobes which mesh with the five 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. Lubricating oil from the oil pan 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 pipe and a passage to the filter head. The oil then flows from the filter head through a pipe to a plate type oil cooler . The oil cooler is located on the left side of the engine. The oil cooler is a plate type oil cooler.From the oil cooler, the oil returns through a pipe to the filter head. The oil then flows from the filter head to the bypass valve and from the bypass valve to the oil filter. The oil flows from the oil filter through a passage that is drilled across the cylinder block to the oil gallery. The oil gallery is drilled through the total length of the left side of the cylinder block. If the oil filter is on the right side of the engine, the oil flows through a passage that is drilled across the cylinder block to the pressure gallery.Lubricating oil from the oil gallery flows through high pressure passages to the main bearings of the crankshaft. Then, the oil 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 and the oil mist. Lubricating oil from the main bearings flows through passages in the cylinder block to the journals of the camshaft. Then, the oil flows from the second journal of the camshaft at a reduced pressure to the cylinder head. The oil then flows into the rocker arm bushing of the rocker arm levers. The valve stems, the valve springs and the valve lifters are lubricated by the splash and the mist of the oil.The hub of the idler gear is lubricated by oil from the oil gallery. The timing gears are lubricated by the splash of the oil. The turbocharger is lubricated by oil from the oil filter through the engine block. An external line from the engine block supplies oil to the turbocharger. The oil then flows through a line to the oil pan.Piston cooling jets are installed in turbocharged engines. The piston cooling jets are supplied with the oil from the oil gallery. The piston cooling jets spray lubricating oil on the underside of the pistons in order to cool the pistons.