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LUBRICATION SYSTEM
SPECIFICATION
GENERAL DESCRIPTION
• Oil in the oil pan is drawn up through a strainer by the oil pump housed at the rear end of the cylinder
block and then lead into the oil cooler where it exchanges heat with cooling water. Then it is lead
through the oil filter and fed into the main oil hole in the cylinder block.
• From the main oil hole, oil is distributed to crankshaft journals, cam shaft and the rocker arm shaft for
lubrication.
• After lubricating each journal position (main bearing) of the crankshaft, the oil then proceeds through the
oil hole in the crankshaft and reaches the pin section to lubricate the large end of the connecting rod.
• Meanwhile, some oil from journal positions on the crankshaft goes into a sub-oil hole and is directed to
the piston cooling jet at each cylinder to cool down each piston.
• Lubrication of the air compressor and supply pump drive gear is provided by oil coming through an oil
passage branching off from the line that leads to the sub-oil hole.
• Oil supplied to the camshaft passes through the oil hole in the camshaft and is distributed to each
journal for lubrication.
• Oil supplied to the rocker arm shaft is distributed through the oil hole in the rocker arm shaft to each
rocker arm bushing for lubrication, and then goes through the oil hole in each locker arm to lubricate
rollers and roller pins.
• Lubrication of each idle gear is provided by oil passing through either the main oil hole or sub-oil hole.
• Pressure of the oil in the system is controlled by a regulator valve so that the standard maximum
pressure of 530±40 kPa (5.4±0.4 kgf/cm
2
) [76.8±5.7 psi] is maintained. When the temperature is low
and oil pressure is high, the safety valve on the oil pump opens [valve opening pressure: 1646 kPa
(16.8 kgf/cm
2
) [239 psi] ] and returns oil to the oil pan.
• Insufficient oil supply due to clogging in the oil cooler or oil filter is prevented by the safety valves [oil
cooler side valve opening pressure: 392±40 kPa (4.0±0.4 kgf/cm
2
) [57±5.7 psi], oil filter side valve
opening presuure: 147±10 kPa (1.5±0.1 kgf/cm
2
) [21±1.4 psi] ].
• Pressure used by the oil pressure switch is taken from the secondary side of the oil filter, and each
piston cooling jet is equipped with a check valve [injection pressure: 245 kPa (2.5 kgf/cm
2
) [36 psi] ] for
appropriate cooling.
Lubrication method
Pressure lubrication by gear pump
Oil filters
Paper filters for both full flow and bypass
Lubricating oil cooler
Water cooled multi plate type
