TM 5-3810-300-24&P-3
Engine Operating Conditions 13.2
71N ENGINES
1200 rpm
1800 rpm
2100 rpm
Lubrication System
Lubricating oil pressure (psi):
Normal ............................................................................................
30-60
38-60
40-60
Minimum for safe operation ............................................................
18
27
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 .......................................................
1.7
4.3
6.0
At max. full-load exhaust back pressure: .......................................
3.2
7.6
10.1
Air inlet restriction (inches water) - full-load speed,
max.:
Dirty air cleaner (oil bath or dry) .....................................................
12.4
25.0
25.0
Clean air cleaner (with pre-cleaner) (oil bath or dry) ......................
8.7
13.4
15.9
Clean air cleaner (less pre-cleaner) (dry).......................................
5.2
9.1
11.5
Crankcase pressure (inches water) - max.:
4-71N engine ..................................................................................
1.8
2.5
2.8
6-71N engine ..................................................................................
2.0
2.8
3.1
Exhaust back pressure (inches mercury) - max.:
Full load ..........................................................................................
1.5
3.3
4.0
No load ...........................................................................................
1.0
2.1
2.6
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
Fuel pump suction at pump 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....................................
160-185
160-185
160-185
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 100 lower.
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