1991/05/20 Caterpillar

Replace Camshaft And Install New Lifters If Pitting, Spalling, Or Wear Occurs On Lobes Of 4N0599 And 4N0602 Camshafts In Fuel Injection Pump Groups{1251,1253}

Usage:

All 3408, 3412 Engines Equipped With Precombustion Chambers

Reference: Service Magazine; September 28, 1987; Page 12; "New Steel Fuel Injection Pump Lifters Should Not Be Mixed With Aluminum Lifters" 3400 Family Of DIT Engines.

Pitting, spalling, and wear can occur on the lobes of the 4N0599 and 4N0602 Camshafts in the fuel injection pump groups for 3408 and 3412 Engines respectively. This problem has been found in the paths where the rollers for the 3S9736 Lifter Assemblies travel over the camshaft lobes.

If pitting, spalling or wear is encountered on the camshaft lobes, Caterpillar recommends installing a new camshaft (the same part number) and different lifter assemblies. Along with a new camshaft, install 8N6981 Lifter Assemblies instead of the original 3S9736 Lifter Assemblies. The 8N6981 Lifter Assemblies have wider rollers which will reduce the stress placed upon the camshaft lobes. Thus, the components will have longer service life.

NOTE: Do not reinstall a used camshaft with new 8N6981 Lifter Assemblies unless the fuel system was originally equipped with 8N6981 Lifter Assemblies.

Caterpillar Information System:

1991/05/20 Procedure To Retain Oil Pump When Pump Mounting Pad On Cylinder Block Is Broken{1201,1304}

1991/05/20 Cylinder Kits Not Recommended For Use In 3400 Family of Marine Engines And D8N Tractors{1214}

1991/05/20 Do Not Weld Repair Worn Wheel Spindles For Off-Highway Trucks Or Wheel Tractor-Scrapers{4002,4205,4234}

1991/05/13 Unwanted Engine Shutdown Caused By "01" And/Or "04" Diagnostic; New "09" Diagnostic Available With 8T9881-8 Electronic Control Module (ECM){4490}

1991/05/13 Engine Updates Help Prevent Piston Seizures{1214,1252,1265,1274,1355,1383,1393,1456}

1991/05/13 Rear Gear (Cam Drive) Groups Improved{1206,1201,1212,7551,7552,7553}

1991/05/13 New Specification For Exhaust Valve Clearance{1123,1121,1105}

1991/05/13 Replacing A 3176...(2YG) Truck Engine With A 1991 3176...(7LG) Truck Engine{1000,1119,1408,1901}

1991/05/13 Component Changes For 1991 Model 3176 (7LGH, 43Z) Engines{1052,1087,1119,1215,1290,1292,1304,1361,1362,1378,1408,1901,1902,1912}

1991/05/13 Larger O-ring Seal Available For Oil Supply Port In Governor Housing{1264}

1991/05/06 New Altronics Interface Boxes{1552,1566}

1991/05/06 Spacers And Longer Bolts Used For Air Inlet Adapters (Plenum Covers) To Prevent Bolt Loosening And Leaks{1058}

1991/05/20 Two Scavenge Screens Now Used In Scavenge Oil Pumps{1312}

1991/05/20 New Speed Setting Clutch Group For 3161 Woodward Governors{1265}

1991/05/20 Correct Testing of Sensing Switches{7400,7402,7422}

1991/05/27 Expected Future Air Conditioning Service Requirements{7320,1802}

1991/05/27 Technical Marketing Information (TMI) System for Commercial Engine Products{0337,0334,0336}

1991/05/27 Smaller Connecting Rod Bolt Used In 4W6425 Air Compressor; Use Correct Torque{1803}

1991/05/27 New Fuel Manifolds And Clamps Reduce Vibration Of Fuel Lines{1252,1702}

1991/06/03 New Deutsch HD-10® Electrical Connectors Used{1400,1408}

1991/06/03 Reference Emissions Graph Helps Determine Oxides Of Nitrogen{1050}

1991/06/03 New Oil Drain Assembly Used; Be Sure To Correctly Tighten Drain Plugs, Port Plugs, And Pipe Plugs In Oil Pans{1302}

1991/06/10 New Timing Specifications For 3500 Spark-Ignited Engines{1552}

1991/06/10 1,1,1-Trichloroethane May Damage Deutsch C-E Electrical Connectors{1400,0645,0785,1450,1550,1900,3168,3225,3418,4294,4323,4450,5485,5700,7400,7450}