TM 9-2815-225-34&P
3-92. ENGINE DYNAMOMETER TESTING (Contd)
LOCATION/ITEM
ACTION
REMARKS
NOTE
At each phase, record crankcase pressure blow-by, engine speed, and load at one-
minute intervals. Watch for increases or wide shifts in blow-by pressure. If a sudden
increase in blow-by pressure occurs or if blow-by exceeds 12" H2O, return to the
previous phase test or repeat phase 1 test and operate engine an additional 15 minutes.
If blow-by does not reach an acceptable level after repeating test for 15 minutes,
discontinue test and determine cause. If blow-by is within an acceptable level, proceed
to next phase test.
After each test, check for fuel, air, water, oil, or exhaust leaks and correct as necessary.
b. Perform phase 2 test. Apply
Refer to phase 2 test in test chart.
load to engine (8) at ±10 percent
horsepower, ±5 percent speed.
Return fuel from injector drain is
Check pressure with blow-by
routed through float tank so when
measuring tool (4). Set idle speed
float tank is filled, float valve
to 600 rpm and set full load
opens and allows return fuel flow
governed speed to 2100 rpm.
to flowmeter. The amount of fuel
Adjust load and rpm until specified
being consumed by engine will
readings are obtained. Set fuel
flow through flowmeter and
rate. Operate air compressor (7)
show rate of fuel consumption
in pumping mode.
in pounds per hour. Turbocharger
engines do not require fuel deaer-
ating below maximum altitudes
shown in table 3-1. Above maximum
altitudes, deaerate at 4 percent for
each 1000 ft (305 m) additional
altitude and 1 percent for each
10°F (-12°C) air temperature rise
above 12°F (-11°C).
c. Perform phase 3 test. Apply
Refer to phase 3 test on table 3-1.
load to engine (8) at ±10 percent
horsepower, ±5 percent speed.
Check crankcase pressure with
blow-by measuring tool (4). Operate
air compressor (7) in pumping mode.
CAUTION
After phase 4 test is completed, allow engine to run at low idle for a minimum of three
minutes before shutting down.
d. Perform phase 4 test. Apply load
Refer to phase 4 test in test chart.
to engine at ±10 percent horse-
power ±5 percent speed. Check
crankcase pressure with blow-by
measuring tool (4). Check for leaks
and retighten all external screws
to correct specifications. Operate air
compressor (7) in non-pumping mode.
NOTE
Readjustment of valves and injectors after one hour of operation is necessary to assure
lowest smoke potential and avoid excessive injector loads.
6.
Valves
Recheck valves.
Refer to para. 3-85.
7.
Injectors
Recheck injectors.
Refer to para. 3-85.
3-686
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