Cummins ISX11.9 CM2250 – Service Manual 001-052   Vibration Damper, Viscous

CAUTION  The silicone fluid in the vibration damper will become solid after extended service, which makes the vibration damper inoperative. An inoperative vibration damper can cause major engine or driveline malfunctions.

• Check the vibration damper for evidence of fluid loss, dents, and wobble.
• Inspect the vibration damper thickness for any deformation or raising of the damper front cover plate.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative battery cable last.

• Disconnect the batteries. Refer to the OEM service manual.
• Remove the cooling fan drive belt. Refer to Procedure 008-002 in Section 8.

Remove two of the vibration damper retaining capscrews.

Install two guide studs into the holes.

Remove the remaining eight capscrews.

Remove the clamping plate, crankshaft pulley, and vibration damper. Refer to Procedure 001-022 in Section 1.

WARNING  When using a steam cleaner, wear safety glasses or a face shield as well as protective clothing. Hot steam can cause serious personal injury.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

Use steam or solvent to clean the vibration damper.

Dry with compressed air.

Always replace the vibration damper after a crankshaft nose malfunction. Crankshaft nose breakages are primarily caused by excessive torsional activity.

The vibration damper must be replaced if the mounting web is cracked or the housing has dents or raised surfaces.

Check the mounting web for cracks.

Check the housing for dents or raised surfaces.

Replace the damper if any of these defects are identified.

Remove the paint on both sides of the vibration damper in four locations, spaced 90 degrees apart.

Measure and record the vibration damper thickness at two points, at each of the four locations.

• Measure the thickness at 3.18 mm [0.125 in] from the outer lip.
• Measure the thickness at 25.4 mm [1.0 in] from the outer lip.

If the variations between any two of the eight measurements exceed 0.25 mm [0.010 in], or if the thickness at any point exceeds 33 mm [1.300 in], replace the vibration damper.

WARNING  Use insulated gloves, Part Number 3823730, when handling heated parts. Hot parts can cause serious personal injury.

To check for oil leaks, spray the damper with crack detection developer, Part Number 3375434, or equivalent.

Heat the damper in an oven, weld side down, for a minimum of 30 minutes, but not longer than 2 hours.

WARNING  Use insulated gloves, Part Number 3823730, when handling heated parts. Hot parts can cause serious personal injury.

Remove the vibration damper from the oven and check for fluid leakage.

If there is leakage, replace the vibration damper.

Make sure the mounting surfaces of the crankshaft nose, vibration damper, and the pulley are clean, dry, and free from burrs.

Install two guide studs into the crankshaft nose.

Install the vibration damper, crankshaft pulley, and clamping plate. Refer to Procedure 001-022 in Section 1.

Clean the outside surface of the vibration damper.

To measure damper eccentricity (out of round), install the dial indicator gauge, Part Number 3376050, and extension Part Number ST-537-4, on the gear cover as indicated.

Rotate the crankshaft with the accessory driveshaft one complete revolution (360 degrees), and record the total indicator movement. Refer to Procedure 009-035 in Section 9.

Vibration Damper Eccentricity

If the vibration damper is not within specifications, it must be replaced.

To measure wobble (face alignment), rotate the crankshaft two complete revolutions (720 degrees) to make sure end play does not affect the measurements. Refer to Procedure 009-035 in Section 9.

NOTE: The rear crank gear on the ISX11.9 is a helical cut gear that will cause the crankshaft to be slightly pulled toward the rear of the engine, when rotated clockwise.

Install the dial indicator as shown.

Push the crankshaft to the rear of the engine and “0” (zero) the indicator.

Rotate the crankshaft one complete revolution (360 degrees) while maintaining the position of the crankshaft toward the rear of the engine. Refer to Procedure 009-035 in Section 9.

Record the total indicator movement.

Vibration Damper Wobble Measurement

If the vibration damper is not within specifications, it must be replaced.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative battery cable last.

• Install the cooling fan drive belt. Refer to Procedure 008-002 in Section 1.
• Connect the batteries. Refer to the OEM service manual.
• Operate the engine and check for proper operation.