Operation; Crankcase Base Cover; Typical Compressor Drive Flanges - BENDIX BA-921 COMPRESSOR-STD-CLOSED ROOM Service Data Sheet

Splash
Shield
Unloader
Cover
Unloader
Piston
Discharge
Reed
Valves (2)
Piston
Piston
Rod
Crankcase
Cover
®
FIGURE 3 - BENDIX BA-921
The compressor's discharge valves are part of the valve
plate assembly. The inlet reed valve/gasket is installed
between the valve plate assembly and the top of the
crankcase.
The cast iron crankcase houses the piston assembly,
connecting rod, crankshaft and related bearings.
All Bendix ® BA-921 ® compressors are equipped with a
safety valve to protect the compressor head in the event
of, for example, a discharge line blockage downstream
of the compressor. Excessive air pressure will cause the
safety valve to unseat, release air pressure and give an
audible alert to the operator. The safety valve is installed
in the cylinder head safety valve port, directly connected
to the cylinder head discharge port.
The crankcase cover located at the bottom of the crankcase
Caterpillar
C7, C9
Engines
FIGURE 5 - TYPICAL COMPRESSOR DRIVE FLANGES
2
Coolant Ports
(3 total)
Air
Intake
Cooling
Plate
Crankshaft
Standard
®
COMPRESSOR (CUT-AWAY) (STANDARD AND CLOSED ROOM)
Caterpillar
HD Acert
Engines
Coolant Ports
(3 total)
Discharge
Reed
Valves (2)
Closed Room
Compressor Model,
Customer Piece Number,
Bendix Piece Number and
Serial Number shown here
FIGURE 4 - CRANKCASE BASE COVER
is stamped with information identifying the compressor
model, customer piece number, Bendix piece number and
serial number. See Figures 1 and 4.

OPERATION

The compressor is driven by the vehicle's engine and
functions continuously while the engine is in operation.
Actual compression of air is controlled by the compressor
unloading mechanism operating in conjunction with a
governor.
Unloader
Cover
Unloader
Piston
Cooling
Plate
Piston
Piston
Rod
Crankshaft
Crankcase
Cover
Detroit
Diesel S60