Stronger Fan Drive Pulley Prevents Cracks During Assembly; Torque On Pulley Bolts Changed{1359}
Usage:
D346 and D348 Industrial Engines
Description of Change: The fan drive pulley and bushing used on D346 and D348 Industrial Engines are made of a stronger material. This will prevent cracks in the pulley at the time it is installed. Also, the torque on the pulley bolts was changed. These bolts are now tightened to 50 ± 10 lb ft (70 ± 14 N·m).
Adaptable As: The new 7N6791 Drive Pulley is a direct replacement for the former 3N647 Drive Pulley which is canceled.
Caterpillar Information System:
1977/09/26 Use Correct Contact Point With Dial Indicator To Be Sure Of The Accuracy Of The Measurements Of Fuel Setting And Fuel Ratio Control Setting On Sleeve Metering Fuel Systems{0653,1250}
1977/09/19 Stronger Piston Is Used; Piston And Connecting Rod Are Tapered In Area Of Piston Pin{1213,1214,1218}
1977/09/19 Use Viscous (Fluid) Type Crankshaft Vibration Damper In Place Of Rubber Type Damper{1205}
1977/09/19 Changes To The Injection Pump And The Fuel Setting{1251,1257}
1977/09/12 New Refrigerant Compressors And Kits With Improved Seals; Conversion Of Earlier Units{7320}
1977/09/12 The Discrepancy Card Has Changed{0374}
1977/09/05 Field Repair Of Cooler Cores Made Of Aluminium{1063,1374,1375}
1977/09/05 Check For Extra Holes In Crankshaft Flange If Oil Leaks From Between The Flywheel And Crankshaft Flange{1156,1202}
1977/09/05 Installation Procedure For Crankshaft Wear Sleeves Changed{1202,1160,1161}
1977/08/29 More Bolts Hold Flywheel Housing Group{1157,1162}
1977/08/29 Anti-Corrosion And Break-In Coatings{0374,3256}
1977/08/29 Engine Valve Springs Are Now Made Of Stronger Steel{1108}
1977/09/26 New Special Instruction Gives General Information On The Use Of The 5P6590 Wiring Harness Tester For Electrical System Testing{0650,1400}
1977/10/03 Change Is Made to Support Beam For Front Of Engine{0643}
1977/10/03 Turbocharger Heat Shields Are Stronger{1073}
1977/10/03 Washer Removed From Variable Timing Unit{1206,1272}
1977/10/03 Do Not Use Plastic Tubing With Brass Couplings As A Fuel Supply Line{1274}
1977/10/10 Be Sure To Drain Oil From The BrakeSaver At Every Lubricating Oil Change Period{1318,1155}
1977/10/10 Fuel Transfer Pump Shaft With Chromium Plate{1256}
1977/10/10 New Front Housing Has Stronger Boss For Alternator{1151}
1977/10/10 Troubleshooting The Tachometer System Of The 4S6553 Engine Instrument Group{0651}
1977/10/10 Use Only The Larger Size Inserts To Make A Repair To Cylinder Block Counterbores For Cylinder Liners{1201,1216,1217}
1977/10/10 Improved Oversize And Undersize Connecting Rod And Main Bearings With Higher Strength Aluminum Alloy{1203,1219,1230}
1977/10/10 If The Fuel Setting Dimension Is More Than 7.00 MM, Remove The End Play Of The Camshaft To Make The Fuel Setting{1257,1286}