TM 5-4310-379-14
Figure 1-6. Air System Diagram.
d. Lubrication System. The lubrication system for the compressor is a pressure type system. A rotary oil pump
located in the carrier bearing assembly pumps oil from the oil pan through a screen assembly and forces oil through the
rifle-drilled crankshaft. This provides lubrication to the connecting rod bearings and piston pin bushings. The main
bearings at each end of the crankshaft are splash lubricated by the action of the crankshaft. This allows oil pressure to
build up. When the compressor slows down the spill valve opens and oil pressure drops. When the spill valve opens, oil
drains from the crankshaft back into the oil pan. The oil pressure is regulated by a spring-loaded ball mounted in the
bearing carrier. Spring pressure is controlled by an adjusting screw. Turning the screw clockwise increases the oil
pressure, turning it counterclockwise decreases the oil pressure. After an adjustment has been made, the adjustment
screw locknut must be tightened.
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