1993/06/14 Caterpillar

New Bonnet Used In Fuel Injection Pump Group {1251}

Usage:

Caterpillar Machines Powered By 3406C (11N) Engines;
3406C (3ZJ, 4CK) Truck Engines;
3406B (6TB) Industrial Engines;
3406B (2WB) Generator Set Engines

Description of Change: A new bonnet is used in the 4P7681 Fuel Injection Pump Group. See the Illustration 1. The new bonnet has two rings on the face that contacts the barrel. See Illustration 2. The inside ring (A) is used for sealing and the outside ring (B) helps support the bushings torque load. The outside ring has one or two notches that go through the ring. These notches prevent high fuel pressure between the rings.

Adaptable To: The new 6I1665 Bonnet is a direct replacement for the former 2W3409 Bonnet and will service all 3406B and 3406C Engines. The former bonnet is canceled. The new bonnet is in effect with:

Caterpillar Machines Powered By 3406C (11N5884) Engines,

3406C (3ZJ32541, 4CK9450) Truck Engines,

3406B (6TB11054) Industrial Engines,

3406B (2WB12514) Generator Set Engines

Illustration 1. Location of new 6I1665 Bonnet (1), and barrel (2) in the 4P7681 Fuel Injection Pump Group.

Illustration 2. Location of sealing ring (A) and load ring (B) on the new 6I1665 Bonnet.

NOTE: Before installing the pumping elements into the pump housing, be sure the pump bores and timing spacers are clean and free of debris.

The tightening torque for the bushing that holds the 4P7681 Fuel Injection Pump Group in the fuel injection pump housing has not changed. Tighten the bushing to a torque of 245 ± 15 N·m (180 ± 10 lb ft).

Caterpillar Information System:

1993/06/14 New Fuel Pump Drive Idler Gear Assembly And Shaft Used In Front Timing Gear Groups {1206}

1993/06/14 Lock Removed From Front Timing Gear Group To Help Prevent Loss Of Tightening Torque {1206}

1993/06/14 Low Idle Adjustment, Additional "Buffer" Adjustment Screw Used On Marine Governors {1264}

1993/06/07 New Electronic Speed Switch Assembly Used In Junction Box Groups Increases Service Life{1900}

1993/06/07 New Jacket Water Heater Mounting Groups Include Improved Hoses{1383}

1993/05/31 New Fuel Injector Group Help Reduce Plunger And Barrel Seizures{1290}

1993/05/24 Summary Of Changes To Timing Advance Drive Groups{1272}

1993/05/17 New Fuel Injection Lines, Clamps, And Brackets Used In Fuel Injection Lines Groups {1252}

1993/05/17 Baffles Available To Help Reduce Turbocharger Noise {1052,1058}

1993/05/10 New Low Crevice Volume (LCV) Piston Body Assembly Used{1214}

1993/05/10 0R3735 Remanufactured Camshaft Available{1210}

1993/05/10 Service Tips For Effective Repair Of Failed Turbochargers{1052,1063,1059}

1993/06/14 3E3761 Coolant Level Sensor Assembly {7422}

1993/06/21 Windshield Washer Jet Nozzle Assembly Available For Parts Service{7306}

1993/06/21 Measuring "Dynamic Rack" Of Unit Injectors{0780}

1993/06/21 New G3500 Gas Engine Performance Manual Available{0376}

1993/06/21 New Cylinder Head Assembly Provides Improved Valve Seat Retention{1100,1103}

1993/07/05 False Logging Of 100-01 Low Oil Pressure, And 100-11 Very Low Oil Pressure Diagnostic Codes {1902}

1993/07/05 New Stronger Elbow Used In Marine And Fire Pump Engine Water Lines Groups {1380}

1993/07/05 New Water Pump Groups Use Tapered Roller Bearing {1361}

1993/07/05 New Cast Iron Inlet Adapter And Impeller For Water Pumps {1361}

1993/07/12 Magnetic Switches (Relays) May Be Intermittent{1400}

1993/07/12 Improved Voltmeters Available{7450}

1993/07/12 Preventive Maintenance To Reduce Risk Of Stator Failure{1404,4453}