ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 012-014   Air Compressor

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.

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  Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.

WARNING  Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

• Disconnect the batteries. Refer to Procedure 013-009 in Section 13.
• Steam clean the air compressor.
• Drain the engine cooling system. Refer to Procedure 008-018 in Section 8.
• Refer to the OEM service manual or remove the hydraulic pump, if equipped. Refer to Procedure 009-016 in Section 9.
• Remove any attachments on the rear of the air compressor. Refer to the OEM service manual.
• Remove the air connections from the air compressor.
• Remove the air governor or air governor signal line, if necessary. Refer to the OEM service manual.
• Remove the air inlet and air outlet connections from the air compressor.

Remove the air compressor support brackets and capscrews.

Remove the two capscrews and the air compressor.

Inspect the compressor housing for cracks or other damage.

Inspect the drive gear for cracks or other damage.

Make sure the gasket surfaces of the front gear housing and the air compressor are clean and not damaged.

Power Steering Coupling (if Applicable)

Inspect the power steering coupling for wear or cracks.

Replace the coupling if damaged. Refer to the OEM service manual.

If the cylinder head are removed, inspect the bare and rotating components within the air compressor.

Inspect the air compressor bore for signs of scoring and polishing.

NOTE: A cross hatch honing pattern must be visible within the bore. If any part of the bore is scored or polished, the air compressor must be replaced.

If internal damage to the rotating assembly (crankshaft, piston, and connecting rod) is suspected, the plug on the bottom of the air compressor must be removed to inpect the rotating assembly.

NOTE: A replacement plug and gasket kit is available for reassembling the air compressor.

Air Compressor Timing (for Single-Cylinder Air Compressor Only)

Rotate the engine so that the number 1 cylinder is at top dead center (TDC) on the compression stroke. This is done by aligning the timing mark on the fuel pump gear with the TDC mark.

NOTE: There are two similar marks on the air compressor gear that look like “[I]” and “I”. The timing mark to be used when timing the air compressor to the engine is “I”.

Holset® Air Compressors

Viewing the compressor from the gear end (with the compressor n a vertical position), rotate the gear so the “I” timing mark is at the 12-o’clock position. This will set the compressor at 60-degrees before top dead center of the compressor’s compression stroke.

NOTE: Some Holset® compressors have a divot or drilling on the housing at the 10-o’clock position; IGNORE this mark.

Cummins® Single-Cylinder Air Compressors

Viewing the compressor from the gear end (with the compressor in a vertical position), rotate the gear so the “I” timing mark is at the 3-o’clock position. The Cummins® single-cylinder air compressor will have a divot on the housing at the 3-o’clock position to aid in timing the compressor. Once the timing mark is at the 3-o’clock position, this will set the compressor at 60-degrees before top dead center of the compressor’s compression stroke.

Air Compressor Timing (for Single-Cylinder Air Compressor Only, Other than Holset® or Cummins®)

Locate TDC on the compressor crankshaft by removing the unloader valve or head. See the respective air compressor manual. TDC does not have to be exact. The system is tolerant of some misalignment.

Use ink or Dykem® marking pen to mark the air compressor gear face at TDC (12-o’clock position when viewed from the front).

Rotate the compressor TDC mark to 60-degrees, or six teeth on a 36-tooth gear, before TDC. This is approximately 10-o’clock when viewed from the front of the air compressor.

Install the air compressor and new gasket to the gear housing.

Install the brace to the air compressor.

Tighten the capscrews.

Install the spacer to brace capscrews and hand-tighten.

Make sure there are no gaps between the spacer and the brace, and no gaps between the spacer and the cylinder block.

Tighten the capscrews.

Install the capscrews that connect the spacer to the cylinder block and hand-tighten.

Make sure there are no gaps between the spacer and the brace, and no gaps between the spacer and the cylinder block.

Tighten the capscrews.

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 oil supply line. Refer to Procedure 012-110 in Section 12.
• Install the air inlet and air outlet connections to the air compressor.
• Install the air governor or air governor signal line, if necessary. Refer to the OEM service manual.
• Install the air compressor coolant lines. Refer to Procedure 012-004 in Section 12.
• Install the air lines.
• Install any attachments to the rear of the air compressor. Refer to the OEM service manual.
• Fill the engine cooling system. Refer to Procedure 008-018 in Section 8.
• Connect the batteries. Refer to Procedure 013-009 in Section 13.
• Operate the engine to activate the air compressor and check for leaks.