TRUCK SERVICE MANUAL
ENGINE
Table 1415: Normal Lubricating Oil Pressure
Idle (525620rpm}
Rated Speed
PSI [kg/sq. cm]PSI [kg/sq. cm]
10 [70] Minimum
40/75 [2.80/5.25]
Note:
Individual engines may vary from above
pressures.
Fuel Pressures
For fuel pressure reading and adjustment, refer to Fuel
Pump Calibration
Overspeed Stop
Overspeed stops, when used, are set to trip and shut off
fuel supply when engine exceeds maximum rated speed
by approximately 15%. After determining and correcting
cause of overspeed stop trip, reset in running position.
Engine Fuel Rate
ST1190 Fuel Consumption Measuring Device operates
by drawing fuel from fuel tank, then through flow meter.
Return fuel from injector drain is routed through float
tank so when float tank is filled, float valve opens and
allows return fuel flow to flow meter. Makeup fuel or
amount of fuel being consumed by engine will flow
through flow meter thus showing rate of fuel
consumption in pounds per hour. See fuel pump
calibration manuals.
Blow-By Readings
1. Manometer readings must be taken frequently during
runin test so mechanic will note any blowby increase at a
given speed and load. If there is any indication of blowby
increase, engine speed must be reduced for a few
minutes and then brought back to the original setting.
2. During each power check, keep a constant check on
the manometer; if pressure rises, more runin is required.
Representative pressure limits for engine running at
governed speed and pulling 96 to 100% of rated
horsepower are given in Table 1414. If pressure is
greater than values listed at end of testing period, engine
should be checked as follows:
a. Naturally aspirated engines:
Operate 30 minutes extra at 96 to 100% rated load and
rpm. If there is no rapid change in excess of 1 inch [25.4
mm] of water and maximum reading does not exceed
100% of representative pressure, blowby is acceptable.
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