TM 5-3810-307-24-2-2
Engine Testing - General Information
The engine test is a combination of an engine run-in and a performance check. The engine run-in procedure
provides an operating period that allows the engine parts to achieve a final finish and fit. The performance check
provides an opportunity to perform final adjustments needed to optimize the engine performance.
An engine test can be performed using either an engine dynamometer or a chassis dynamometer. If a dyna-
mometer is not available, an engine test must be performed in a manner that simulates a dynamometer test.
Check the dynamometer before beginning the test. The dynamometer must have the capability to test the
performance of the engine when the engine is operating at the maximum RPM and horsepower range (full power).
The engine crankcase pressure, often referred to as engine blowby, is an important factor that indicates when the
piston rings have achieved the correct finish and fit. Rapid changes of blowby or values that exceed specifications
more than 50 percent indicate that something is wrong. The engine test must be discontinued until the cause has
been determined and corrected.
General Engine Test Specifications
Maintain the following limits during a chassis dynamometer test:
Intake Restriction (Maximum)
Clean Filter (light duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 mm H20
[10 in. H20]
(medium duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 mm H20
[12 in. H20]
(heavy duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 mm H20
[15 in. H20]
Dirty Filter (light duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635 mm [25 in.]
(medium duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635 mm [25 in.]
(heavy duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635 mm [25 in.]
Exhaust Back Pressure (maximum)
Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 mm Hg [3.0 in. Hg]
EPA Certified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 mm Hg [4.5 in. Hg]
Oxidation Catalyst.............................................................................. 152 mm Hg [6.0 in Hg]
Blowby** (at Given Speed, 100% Load)
New (L/Min)
Worn (L/Min)
66 @ 2800
34
68
6BT/6BTA/B5.9 @ 2200
63
126
6BT/6BTA/B5.9 @ 2500
76
152
6BT/6BTA/BS.9 @ 2800
85
170
**Blowby checking tool, Part No. 3822476, has a special 5.613 mm [0.221 in.] orifice that must be used to get an
accurate reading.
Oil Pressure
Low Idle (minimum allowable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 kPa [10 psi]
Rated Speed (minimum allowable).................................................................. 207 kPa [30 psi]
Fuel Filter Restriction (Maximum pressure drop across filter)
Dirty Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 kPa [5 psi]
Fuel Return Restriction (Maximum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518 mm Hg [20.4 in hg]
NOTE
Due to variations in ratings of different engine models, refer to the specific engine data
sheet for the particular engine model being tested.
