The oil pump (fig. 1) is two-section, gear. The upper section of the oil pump supplies oil to the engine lubrication system and centrifuge, while the lower section supplies oil to the oil cooler
Reducing valve 3, built into the oil pump cover, is adjusted to a pressure of 3.2 kg/cm2 (at least) and bypasses oil from the pressure cavity of the oil pump to the suction one.
The minimum allowable oil pressure in the engine, warmed up to operating temperature, should be 0.5 kg/cm2 at idle (500 rpm) and 1.5 kg/cm 2 at 1200 crankshaft revolutions per minute.
The lower section of the oil pump supplies oil to the oil cooler.
The bypass valve built into the lower section of the oil pump is set to 1.2 kg/cm2.