TM 5-3895-359-14&P
OPERATING CONDITIONS
CHAPTER 9
CONTENTS
PAGE
Engine Operating Conditions ........................................................................................................ 10-9-1
Engine Run-In Instructions ........................................................................................................... 10-9-2
Fuels, Lubricants and Coolants ..................................................................................................... 10-9-7
ENGINE OPERATING CONDITIONS
The engine operating charges are included as an aid for engine operation and trouble shooting. Any variations from the
conditions as listed may indicate an abnormal situation in need of correction. Make sure that the readings represent true
values, and that instruments are accurate, before attempting to make corrections to the engine.
71N ENGINES
1200 rpm
1800 rpm
2100 rpm
Lubrication System
Lubricating oil pressure (psi):
Normal.............................................................................................. 30-60
43-65
45-65
Minimum for safe operation .............................................................. 18
28
30
*Lubricating oil temperature (degrees F.):
Normal.............................................................................................. 200-225
200-225
200-225
Air System
Air box pressure (inches mercury) - min. at full load:
At zero exhaust back pressure:
N injectors.........................................................................................
0.1
2.8
4.6
At max. full-load back pressure:
N injectors.........................................................................................
1.2
5.3
7.6
Air inlet restriction (inches water)-max. full-load:
Dirty air cleaner ...............................................................................
12.4
25.0
25.0
Clean air cleaner ..............................................................................
5.2
9.1
11.5
Crankcase pressure
4-71N engine ...................................................................................
1.8
2.5
2.8
Exhaust back pressure (inches mercury) - max.
Full load............................................................................................
1.5
3.3
4.0
Fuel System
Fuel pressure at inlet manifold (psi):
Normal (.080" orifice) ........................................................................ 30-65
45-70
45-70
Fuel spill (gpm) - min. at no load:
(.080" orifice) .................................................................................... 0.8
0.9
0.9
Pump suction at inlet (inches mercury) - max.:
Clean system ................................................................................... 6.0
6.0
6.0
Dirty system ...................................................................................... 12.0
12.0
12.0
Cooling System
Coolant temperature (degrees F.) - normal (Veh.) .................................. 170-195
170-195
170-195
Compression
Compression pressure (psi at seal level):
Average - new engine at 600 rpm ........................................ 565
Minimum at 600 rpm ............................................................. 515
*The lubricating oil temperature range is based on the temperature measurement in the oil pan at the oil pump inlet.
When measuring the oil temperature at the cylinder block oil gallery, it will be approximately 10lower than the oil pan
temperature.
10-9-1
