TM-9-2320-260-20

TRUCK, 5-TON, 6X6, M809 SERIES (DIESEL)

TECHNICAL MANUAL; UNIT MAINTENANCE

APRIL 1995
TM-9-2320-260-20

  TM-9-2320-260-20 - Page 338 of 1337

3-1
3-2
TM 9-2320-260-20
CHAPTER 3
ENGINE SYSTEMS MAINTENANCE
Section I.
Section II.
Section III.
Section IV.
Section V.
Section VI.
Section VII.
Engine Lubrication System Maintenance (page 3-1)
Clutch System Maintenance (page 3-16)
Air Intake System Maintenance (page 3-23)
Fuel System Maintenance (page 3-32)
Accelerator System Maintenance (page 3-68)
Exhaust System Maintenance (page 3-74)
Cooling System Maintenance (page 3-84)
a. The Cummins NHC-250 diesel engine is used on all M809 series vehicles. It is a naturally-aspirated,
liquid-cooled, overhead valve, four-cycle engine of in-line, six-cylinder design. The NHC-250 engine has
a compression ratio of 15.8 to 1 and develops 240 horsepower at 2100 rpm. Peak torque is 560 lb-ft at
1600 rpm.
b. Both early model engines, serial number 1124663 and before, and late model engines, after serial
number
1124663, are covered in this
chapter. The differences between early and late models are changes
to implement the clean air configuration and the use of top stop fuel injectors. Changes to the clean air
configuration provide for controlled engine exhaust gas recirculation back to the air intake manifold.
The tip stop fuel injectors are different from early model engine injectors in that the adapter is lower to
accomodate the stop. The plunger coupling top is smaller and has an adjustable stop screw and locknut.
Identification of both early and late model engines can be made horn the engine identification plate on the
left side of front gearcase cover.
Section I. ENGINE LUBRICATION SYSTEM MAINTENANCE
PARA.
NO.
TITLE
PAGE
NO.
3-3.
3-4.
3-5.
3-6.
3-7.
3-8.
3-9.
3-10.
Oil Dipstick and Tube Replacement
Crankcase Breather Maintenance
Engine Oil Filter and Housing Maintenance
Oil Pressure Piping Replacement
Engine Draft Tube Replacement
Oil Pump Pickup and Return Hose Replacement
Front Sump Tube Replacement
Engine AOAP Maintenance
3-2
3-4
3-6
3-8
3-10
3-12
3-13
3-14
3-1


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