Cummins ISX11.9 CM2250 – Service Manual 003-999   Rocker Levers – Overview

Valves and engine brakes (if equipped) must be correctly adjusted for the engine to operate efficiently. Valve and engine brake adjustments must be performed using the values listed in this section.

Adjust the valves and engine brakes according to the schedule outlined in the ISX11.9 CM2250 Operation and Maintenance Manual, Bulletin 2883444. Refer to Procedure 102-002 in Section 2. Adjustment must also be made after any major repair.

Use the following procedure for valve and engine brake adjustment values. Refer to Procedure 003-004 in Section 3.

Crankcase Breather – The  ISX11.9 CM2250 crankcase breather is a design that vents to the atmosphere. The crankcase breather is mounted on the left side of the engine above the valve cover. Oil vapor is separated and condensed in the breather housing and is returned to the oil pan by external plumbing into the cylinder block.

Replace the crankcase breather element according to the schedule outlined in the ISX11.9 CM2250 Operation and Maintenance Manual, Bulletin 2883444. Refer to Procedure 102-002 in Section 2.

Rocker Lever Housing – The aluminum rocker housing is separate from the rocker lever assembly. The rocker lever housing can be removed with the rocker levers in position. There is a pass-through port in the rocker lever housing that accommodates the injector and engine brake harnesses.

CAUTION  There are two rocker lever shaft assemblies: front and rear. Be sure to position the rocker lever support assemblies in their proper location. If the engine is equipped with a compression brake, the proper rocker lever support must be located at the center of the cylinder head, rocker lever shaft positions 3 and 4, to supply the compression brake with oil. Failure to properly position the rocker lever supports will prevent the compression brake from operating.

Rocker Lever Assembly – There are two separate rocker lever assemblies, referred to as Front and Rear. The intake and exhaust rocker levers are unique for the front and rear assembly. Do not intermix the intake and exhaust levers between front and rear assemblies.

To identify the difference between the exhaust and the intake rocker lever, the longer rocker lever is the exhaust lever. The shorter rocker lever is the intake lever. The rocker levers use an “elephant foot” design versus a “ground foot” design.