Electronic Injector Height Adjustment and Setting{1251, 1290} Caterpillar

Articulated Truck:

735 (S/N: B1N1-UP)

740 (S/N: B1P1-UP)

Cold Planer:

PM-200 (S/N: P1C1-UP)

PM-201 (S/N: PNM1-UP)

Landfill Compactor:

826H (S/N: AWF1-UP)

836H (S/N: BXD1-UP)

Soil Compactor:

825H (S/N: AZW1-UP)

Industrial Engine:

C15 (S/N: JRE1-UP)

C15 (S/N: JAS1-UP)

C18 (S/N: WJH1-UP)

C18 (S/N: EJG1-UP)

Petroleum Engine:

C32 (S/N: SMP1-UP)

Excavator:

365C (S/N: GWC1-UP; FEN1-UP; PAR1-UP; MCS1-UP)

385C (S/N: EDA1-UP; MMA1-UP; T2E1-UP; T2F1-UP; EAM1-UP; JCM1-UP; GLT1-UP; WAW1-UP; MNZ1-UP)

Load Haul Dump:

R2900G (S/N: JLK1-UP)

Road Reclaimer/Soil Stabilizer:

RM-500 (S/N: ASW1-UP)

Track-Type Tractor:

D8T (S/N: J8B1-UP; KPZ1-UP)

D9T (S/N: RJS1-UP)

Underground Articulated Truck:

AD30 (S/N: DXR1-UP)

AD45B (S/N: CXM1-UP)

AD55 (S/N: DNW1-UP)

Wheel Dozer:

824H (S/N: ASX1-UP)

834H (S/N: BTX1-UP)

844H (S/N: BTW1-UP)

Wheel Loader:

980H (S/N: MHG1-UP; A8J1-UP; JMS1-UP)

988H (S/N: BXY1-UP)

990H (S/N: BWX1-UP)

Wheel Tractor-Scraper:

621G (S/N: DBB1-UP)

623G (S/N: DBC1-UP)

627G (S/N: DBD1-UP)

Introduction

Injector height setting is extremely important during the engine assembly process. The recommended intervals that are specified in the Operation and Maintenance Manual must be followed.

Problem

An issue has been identified with the correct injector height settings. Check the injector height. Bottoming of the fuel injector rocker arm may be caused by the injector height being to high or low. Bottoming of the fuel injector can create a crack at the nose of the fuel injector rocker arm through the first and second threads of the adjusting screw hole. Once the crack has started it can result in the breaking of the fuel injector rocker arm at the nose. Breaking of the fuel injector rocker arm will result in an immediate poor engine performance.

Solution

Performing the recommended inspection of the fuel injector rocker arm at the specified intervals in the operation and maintenance manual is important. Inspect the height of the unit injectors with the 9U-7227 Injector Height Gauge . If the injector height on any cylinder is more than one half of a turn high or low, there could be the potential for early fatigue or cracking and breaking through the nose of the fuel injector rocker arm. If any of the unit injectors are found to be set more than one half of a turn high or low, it is recommended that the fuel injector rocker arm is removed and replaced with a new rocker arm that is the same part number. Set the new rocker arm to the correct height. Tighten the adjusting nut to the correct torque specifications.

The following instructions are for the adjusting of unit injector height on C15, C18, and C27 applications.

Use the following procedure in order to make an adjustment to the unit injectors on cylinders 3, 5, and 6.

Illustration 1	g01242010
(1) Fuel injector rocker arm (2) Adjusting screw (3) Locknut (4) 9U-7227 Injector Height Gauge

1. Put the No. 1 piston at the top center position on the compression stroke. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston".

2. Injector height gauge (4) is used in order to obtain a dimension of 78.0 ± 0.2 mm (3.07 ± 0.01 inch). The dimension is measured from the top of the unit injector to the machined ledge of the fuel injector body. Turn the unit injector adjusting screw (2) clockwise until the correct height is obtained.

3. Hold the adjusting screw in this position and tighten locknut (3) to a torque of 100 ± 10 N·m (74 ± 7 lb ft).

4. To make an adjustment to the unit injectors on cylinders 1, 2, and 4, remove the timing bolt. Turn the flywheel 360 degrees in a counterclockwise rotation. The engine is viewed from the flywheel end. This will put the number 1 piston at the top center position on the exhaust stroke.

5. Repeat steps 3 and 4.

Note: Remove the timing bolt from the flywheel after all of the unit injector adjustments have been made. Reinstall the valve mechanism cover.