Cummins ISX11.9 CM2250 – Service Manual 001-036   Idler Gear, Camshaft

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. Refer to Procedure 008-040 in Section 8.
• Remove the front gear cover. Refer to Procedure 001-031 in Section 1.

To remove the camshaft idler gear assembly, remove the following:

• Small capscrews (two)
• Large capscrews (two)
• Idler gear shaft
• Front thrust bearing
• Rear thrust bearing.

Mark or tag the individual pieces of the idler gear assembly and attach them together.

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.

Clean the parts with solvent.

Dry with compressed air.

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

Use a bristle brush to clean the oil drillings in the idler gear shaft.

Blow out the oil drillings with compressed air.

Use a straightedge to inspect the retaining capscrews for necking.

If necking is observed, do not reuse the capscrews. They must be replaced.

Inspect the idler gear for chipped, broken, or cracked teeth.

Measure the inside diameter of the idler gear bushing bore.

Camshaft Idler Gear Bushing Bore Inside Diameter

Measure the outside diameter of the idler gear shaft.

Camshaft Idler Gear Shaft Outside Diameter

Measure the thrust washer thickness in three places, 120-degrees apart.

Camshaft Idler Thrust Washer Thickness

Flex the thrust washers approximately 3 to 6 mm [1/8 to 1/4 in], and inspect the surfaces for cracks.

Replace the thrust washer if cracks are observed.

Use lubricant such as Lubriplate™ 105, or equivalent, to lubricate the thrust bearings and idler gear shaft.

Install the ring dowel into the back of the idler gear shaft.

Assemble the thrust bearings and idler gear onto the idler gear shaft in the following order:

• Front thrust bearing
• Idler gear
• Rear thrust bearing.

Install the assembly onto the gear housing.

Install the four capscrews. Tighten the capscrews tight enough to hold the gear in place, but loose enough to allow for adjustment.

Insert a 0.0635 mm [0.0025 in] feeler gauge into the gear teeth mesh between the camshaft idler gear and the camshaft gear (1) as illustrated.

Insert a 0.0635 mm [0.0025 in] feeler gauge into the gear teeth mesh between the camshaft idler gear and the accessory drive (air compressor) gear (2), as illustrated.

Apply hand pressure to the camshaft idler gear shaft, such that the camshaft idler gear is pushed up tightly into the gear meshes of the other gears.

Make sure the feeler gauges are properly located between the teeth of the gears.

While holding the gear in position, tighten the two larger (M12) capscrews.

Tighten the two smaller (M10) capscrews.

Remove the shims.

A slight drag should be felt on the shims while pulling the shims out.

Check the idler gear backlash. Refer to Procedure 001-055 in Section 1.

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 front gear cover. Refer to Procedure 001-031 in Section 1.
• Install the cooling fan. Refer to Procedure 008-040 in Section 8.
• Connect the batteries. Refer to the OEM service manual.
• Operate the engine and check for leaks and proper operation.