Improved Camshafts and Rocker Arm Assemblies Are Now Available For Hydraulic Mining Shovels and Rotary Drills Equipped with C27 and C32 Engines {1123, 1210} Caterpillar

Industrial Engine

C27 INDUSTRIAL (S/N: TWM1-UP)

C32 INDUSTRIAL (S/N: TLD1-UP)

Introduction

This Special Instruction provides information for the improved camshafts, and rocker arms used on C27 and C32 Engines.

Note: The high-pressure oil pump update mentioned in Special Instruction, REHS9247 is not required for block mounted oil filter applications. The high-pressure oil pump is only required for engine applications with a remote oil filter base installed.

Improved Rocker Arms

The new rocker arms have a coated pin that provides less friction at the roller and pin contact area. This reduced friction decreases the stress between the roller and the camshaft lobe.

The new rocker arms are direct replacement for former rocker arms. The new rocker arms are adaptable back to the first production on C27 and C32 Engines installed in Hydraulic Mining Shovels, Rotary Drills, and all other Engines.

Illustration 1	g03695202
(1) Valve Rocker Arm (2) Injector Rocker Arm (3) Coated Roller pin

This change is effective at the factory with engine build date of 13 March 2014, and 04 March 2014for Tier IV-specific engines.

Illustration 2	g03681160
Typical 384-1367 Valve Rocker Arm Visual reference chart for base level part identification (4) New oil path

Illustration 3	g03741305
Visual reference chart for base level part identification The upper pictures directly below the part numbers show a cut away of the rocker arms, with or without, the oil paths. The lower pictures show the complete rocker arms for the same part numbers above. (5) Oil paths (6) 203-8823 Rocker Arm (7) 243-2465 Rocker Arm (8) 259-6121 Valve Rocker Arm (9) 271-3962 Valve Rocker Arm (10) 274-5351 Rocker Arm (11) 322-9169 Rocker Arm

Former rocker arms included various improvements, most recently the addition of an oil hole for the cam roller outer surface, shown in Illustrations 2 and 3.

Progression of Rocker Arms Groups

Refer to Table 2 for the progression of rocker arm part numbers.

Improved Camshafts

Exhaust and intake camshaft lobe profiles were improved by increasing the width of the lobes. This improvement provides a more uniform surface profile across width of the lobe.

Note: Some remanufactured camshafts with a former Reman part number may still utilize former design dimensions, and will not have a wider lobe. Improvements have already been introduced to achieve the same uniform profile as compared to new part numbers.

The change is effective at the factory with engine build date of 02 January 2013.

The change is effective with Reman engines built on or after 02 January 2013.