N14 Base Engine Troubleshooting and Repair Manual – 014-006   Engine Run-in (Engine Dynamometer)

Measurements from these indicators and gauges

must
be observed closely during all phases of the engine run-in period. Engine measurements taken are:

• Engine speed
• Engine horsepower
• Lube oil pressure
• Lube oil temperature
• Coolant out temperature
• Fuel pressure
• Crankcase blowby
• Fuel rate (using fuel measuring device, Part No. 3376375)
• Intake manifold air temperature
• Intake manifold pressure
• Turbocharger inlet air temperature

Refer to the Engine Dynamometer worksheet in Procedure 014-001-056.

Cummins Engine Company, Inc. recommends monitoring block coolant pressure during run-in to aid in early indication of a cooling system problem.

It is a good practice to observe these measurements even if engine performance meets specifications. If engine performance does

not
meet specifications, these measurements can indicate possible reasons for underperformance. The measurements taken are:

• Fuel inlet restriction at fuel pump inlet
• Fuel temperature
• Exhaust system back pressure
• Air inlet restriction pressure
• Fuel drain pressure
• Coolant pressure
• Oil patch test

Obtain the CPL number from the engine dataplate and the fuel pump code from the fuel pump dataplate. Engine performance specifications and fuel system calibration values for specific engine CPL and fuel pump codes are listed in the following publications:

1. Fuel Pump Calibration Values, Bulletin No.

   3379352.

2. Injector Parts Flow and Cross Reference, Bulletin No.

   3379664.

3. Engine Data Sheets.

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 during the next step, discontinue the run-in and determine the cause.

Do

not
proceed to the next step until a steady blowby reading is obtained.

NOTE: Blowby

must
be measured by using blowby checking tool, Part No. 3375150 or 3822566, with a manometer, Part No. ST-1111-3, or its equivalent. Blowby checking tool, Part No. 3375150, as shown, utilizes a chamfered 7.67 mm [0.302 inch] orifice.

Start the engine.

Move the throttle to obtain 1200 rpm engine speed, and apply a test load sufficient to develop 25 percent of rated fuel pressure or 25 percent fuel rate on CELECT™ and CELECT™ Plus engines.

Operate the engine at this speed and load level until the coolant temperature is 70°C [158°F]. Check all gauges and record the data.

Open the throttle to obtain speed at which maximum horsepower is developed, and adjust the dynamometer load to achieve 75 percent of rated fuel pressure or 75 percent fuel rate on CELECT™ and CELECT™ Plus engines. Operate the engine at this speed and load level for 3 minutes.

Check all gauges and record the data.

NOTE: Do

not
proceed to the next step until blowby is stable within specifications.

Move the throttle lever to its fully opened position, and increase the dynamometer load until 100 percent rated fuel pressure or 100 percent fuel flow on CELECT™ and CELECT™ Plus engines is developed. Operate the engine at this condition and load level for 5 minutes or until the blowby becomes stable within specifications.

Check all gauges and record the data.

Increase the dynamometer load until the engine speed reduces to the engine’s torque peak rpm.

Operate the engine at torque peak rpm for 7 minutes.

Check all gauges and record the data.

Reduce the dynamometer load until the engine speed increases to the engine’s maximum horsepower rpm.

Operate the engine at maximum horsepower rpm for 5 minutes.

Check all gauges and record the data.

Compare the readings to the specifications listed in the previously mentioned publications.

CAUTION  Shutting off the engine immediately after operating at full load will damage the turbocharger and internal components. Always allow the engine to cool before shutting it off.

Remove the dynamometer load completely, and operate the engine at 700 to 900 rpm for 3 to 5 minutes. This period will allow the turbocharger and other components to cool.

Shut off the engine.

Make sure all instrumentation is removed before removing the engine from the engine dynamometer.