1997/08/01 Caterpillar

Fuel Injector Trim Set Screw {1290}

Usage:

3606 (8RB),
3608 (6MC),
3612 (9RC, 9FR),
3616 (1PD, 1FN) Engines

A trim set screw (1) is provided on the injectors to adjust the rack (2) zero point AT THE FACTORY ONLY. This set screw should NOT be moved, adjusted, or tightened in the field. There have been instances where customers have mistaken this set screw for a fastener rather than an adjustment. If a unit injector is found to have a loose trim set screw; or if the set screw has been moved, tightened, or adjusted, the unit injector must be removed from the engine and completely recalibrated. This calibration is a FACTORY ADJUSTMENT ONLY.

When the trim set screw is loose or has been moved, the injector can not be synchronized with the gauge block. An imbalance of fuel going into each cylinder can result. This can cause unequal power output from each cylinder.

Location of the trim set screw (1) and rack (2) in a typical unit injector.

Caterpillar Information System:

1997/08/01 New Schedule For Cleaning Unit Injectors In Engines In Heavy Fuel Oil (HFO) Applications {1290}

1997/08/01 New Gear Assemblies With A Stronger Shaft Are Used In Governor Drive Groups {1288}

1997/08/01 Procedures For Changing From Running On Heavy Fuel Oil (HFO) To Running On Distillate Fuel {1280}

1997/08/01 Connecting Rod Bearing Part Numbers {1203,1219,1230}

1997/08/01 Crankshaft Oil Passage Plugs {1202}

1997/08/01 New Torque Specification For Some Bolts In Valve Mechanism Group {1102,1123}

1997/08/01 Revised Starting Procedure For Engines Using Kiene Valves {1100}

1997/08/01 New Manual Valve Group [Measure Cylinder Pressure (Kiene® Valve)] Used; Kiene Valve Installation Procedure {1100,1118}

1997/08/01 Installation Procedure For Cylinder Head Studs {1100}

1997/08/01 Changes To Cylinder Head Salvage Procedure {1100}

1997/08/01 Air Quality Requirements For Turbocharger Air Impingement System {1052}

1997/08/01 New Specification For Clearance Between Turbocharger Turbine Wheel Blades And Turbine Wheel Cover Ring {1052}

1997/08/01 Guidelines For Electrically Grounding Gas Engines {7423}

1997/08/01 Changes To Default Overcurrent Settings For EMCP II+ {4490}

1997/09/15 New Dual Stage Torsional Coupling Assembly Available For Use With Twin Disc MG 514C Marine Transmissions{3357}

1997/09/15 3406C Pump And Governor Changes Provide Improved Oil And Fuel Leak Resistence{7555}

1997/09/15 Improvements Made For Exhaust Manifold Groups{1059}

1997/09/15 New Exhaust Shield Groups Use Soft Wrap Insulation Instead Of Hot Box Shielding{1067}

1997/09/15 Instrument Panel Lines Groups Changed In Order To Improve Mounting Of The Fumes Disposal Group{1071}

1997/09/15 New Spark Plug On G3500 Engines Improves Reliability{1555}

1997/09/15 Self-Locking Bolt Used On Cylinder Block Cover Groups{7553}

1997/09/15 Stainless Steel Bolts Replace The Former Waspaloy Bolts{1059}

1997/09/15 Bellows Replaces Flange And Pipe In Water Aftercooler Groups{1063}

1997/09/15 New Manifold Soft-Wrap Shields Improve Reliability{1067}