Workshop Manual, TSD3450E, Issue 1 95
10
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Lubrication system 10
General information
A wet sump type of lubrication system is used on the engine.
The engine is fitted with a lubricating oil pump, of the spur gear type, which is driven by a helical gear. The
helical gear is driven by a gear on the front of the crankshaft. The oil pump draws oil from the sump through a
suction strainer. A pressure relief valve, integral with the oil pump, ensures that a constant pressure is
maintained.
Oil leaves the oil pump and is delivered to the main oil gallery in the crankcase. When the engine is warm, the
oil passes through the oil cooler and oil filter before it enters the main oil gallery. When the engine is cool, the
high viscosity of the oil causes the by-pass valves to open and provide oil directly to the oil filter. To protect the
engine, the by-pass valves will also open if there is a restriction in the oil cooler or the oil filter.
A supply of oil is directed to the turbocharger from the oil filter. After lubricating the turbocharger bearings, the
oil drains into the crankcase and returns to the sump.
The main oil gallery is parallel to the crankshaft and supplies oil to each of the main bearings and through the
main bearings to the crankshaft. The oil in the crankshaft then lubricates the connecting rod bearings. A supply
of oil from the main oil gallery is directed to the piston cooling jets which cool the pistons.
An oil passage at the front end of the main oil gallery delivers oil to the cylinder head gallery and has passages
which supply the bearings of the drive gears. The teeth of the drive gears are lubricated by spill oil as it returns
to the sump.
Small holes in the cylinder head gallery direct oil to the camshaft bearing journals and also to the pedestals for
the rocker shafts. From the pedestals the oil passes through the rocker shafts to lubricate the bearings of the
valve and unit injector rocker levers. Oil flows through drilled passages in the rocker levers to lubricate the
rollers, the valve bridges and the contact surfaces of the actuators for the unit injectors. Other components of
the valve assembly are lubricated by splash oil. An aperture at the front of the cylinder head allows oil to drain
to the sump.
The full length sump is manufactured from a composite material.
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