Cummins ISX11.9 CM2250 – Service Manual 020-024   Engine Brake

Check that the correct wiring harness is installed. The engine can be equipped with either a Brake harness or a Non-Brake harness.

Install the correct harness if not present. Refer to Procedure 019-063 in Section 19.

Check that the compression brake crossheads are installed and verify the actuator pins are facing the camshaft side of the engine.

Oil feed adapters must be installed in the rocker lever pedestals. If the oil feed adapters are not installed, perform the following:

• Remove any pedestal plugs from the oil feed drilling
• Be sure o-rings are undamaged and installed on the adapters
• Install the oil feed adapters into rocker lever pedestals.
• Tighten the oil feed adapters.

Install six mounting studs into the holes in the cylinder head. The allen socket should be pointing up.

Hand-tighten the studs until bottomed in the tapped hole.

Install a mounting spacer on each stud.

Install the brake housing marked “Front” onto the studs for cylinders 1 through 3.

Install the brake housing marked “Rear” onto the studs for cylinders 4 through 6.

Install the mounting capscrews and washers through the left side of the brake housing and into the rocker shaft supports.

Install the mounting nuts onto the mounting studs.

Snug all fasteners.

Tighten the mounting hexagonal nuts and mounting capscrews starting with the center fastener and working outward, as shown in the illustration.

Tighten the engine brake mounting capscrews.

Connect the solenoid power and ground wires to the terminals and tighten.

Adjust the slave piston clearance. Use the Adjust section in this procedure.

CAUTION  Do not tighten the adjusting screw too tightly. The engine can be damaged.

CAUTION  Failure to have the correct clearance can damage the engine.

To obtain maximum brake operating efficiency, and prevent engine damage by piston-to-valve contact, complete the following instructions carefully.

After adjusting the exhaust valves on the appropriate cylinder, insert the correct feeler gauge.

Loosen the locknuts on the slave piston adjusting screws.

Rotate the engine to the desired position marked on the front engine damper.

Use Cummins® service tool, Part Number 4919693, to adjust the brake lash for the corresponding cylinders to 3.8 mm [0.150 in] of clearance.

Once properly adjusted, hold the adjusting screw in position and tighten the locknut.

After the secondary piston adjusting screw locknut is tightened to the correct torque value, check the clearance with the feeler gauge again.