The following procedure assumes that the lubricating oil and fuel systems were correctly primed, the dipstick cal
ibrated, and the engine filled to the correct levels with lubricating oil and coolant during installation of the engine
into the chassis. If these systems were not serviced during installation of the engine, refer to Engine Dynamometer Test – Installation of the Engine (8-01) for instructions on priming the lubricating oil and the fuel systems and
calibrating the dipstick. Refer to the latest B Series Operation and Maintenance Manual, Bulletin No. 3810205,
for instructions on filling the lubricating oil and the cooling systems.
The number of instruments and gauges required to perform a chassis dynamometer test will vary according to
the type and the capability of the test equipment used.
Refer to pages 8-4 and 8-5 for the correct system pressure and temperature gauge connecting locations.
To correctly monitor an engine’s performance, record the following parameters:
• Exhaust Back Pressure
• Lubricating oil pressure (vehicle instrument panel)
• Coolant temperature (vehicle instrument panel)
• Coolant pressure*
• Intake manifold pressure*
• Inlet air restriction*
• Blowby*
• Engine speed (RPM) (vehicle instrument panel)
• Wheel horsepower (WHP) (dynamometer controls)
*See the following for the Service Tools required and the installation locations on the engine.
Measure the coolant pressure at the cylinder head, rear fuel pump side.
Minimum Gauge Capacity: 415 kPa [60 psi]
Measure the intake manifold pressure (turbocharger boost). Install a pressure gauge, Part No. ST-1273, in the
location shown.
Minimum Gauge Capacity: 1905 mm Hg [75 in. Hg]
Connect a water manometer to the turbocharger air inlet pipe to test air restriction.
NOTE: The manometer connection must be installed at a 90 degree angle to the air flow in a straight section of pipe, one pipe diameter before the turbocharger.
NOTE: A vacuum gauge can be used in place of the water manometer.
Minimum Gauge Capacity: 760 mm H20 [30 in. H20 ]
Measure the blowby by installing blowby checking tool in the crankcase breather vent. Connect the blowby tool to
a water manometer.
NOTE: Excessive blowby indicates a turbocharger malfunction or an engine internal components malfunction, allowing combustion gases to enter the crankcase.
Minimum Gauge Capacity: 1270 mm H20 [50 in. H20]
NOTE: If a sudden increase in blowby occurs, or if blowby exceeds the maximum allowable limit during any run-in step, return to the previous step and continue the run-in. If blowby does not reach an acceptable level, discontinue the run-in and determine the cause.
NOTE: Avoid long idle periods. Operate the engine at low idle only long enough (3 to 5 minutes) to check for correct
lubricating oil pressure and any fuel, lubricating oil, water, or air leaks.
Caution: Do not allow the engine speed to exceed 1,000 RPM before run-in. The internal components can be damaged.
Caution: Do not shut off the engine immediately after the last step of the run-in is completed. Allow the engine
to cool by operating at low idle for a minimum of 3 minutes to avoid internal component damage.
