Stronger Fan Drive Pulley Prevents Cracks During Assembly; Torque On Pulley Bolts Changed
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:
1977/09/07 List Of Service Publications
1977/09/07 Check For Extra Holes In Crankshaft Flange If Oil Leaks From Between The Flywheel And Crankshaft Flange
1977/09/07 New Tube Assemblies For Turbocharger Oil Lines; New Base Assemblies For Oil Filters
1977/09/07 Engine Valve Springs Are Now Made Of Stronger Steel
1977/09/07 New Clutch Groups Used In Front Power Take-Offs; Service Kits Available
1977/09/07 Installation Procedure For Crankshaft Wear Sleeves Changed
1977/08/24 Be Sure To Drain Oil In BrakeSaver At Every Lubricating Oil Change Period
1977/08/24 Installation Of Generator Sets On Rigid Bases
1977/08/24 Larger Boss Used In Cylinder Block So Bolt Hole Will Not Be Drilled Into Coolant Passage
1977/08/24 Improved Coolant Seal For Connection Between Cylinder Heads
1977/08/24 More Bolts Hold Flywheel Housing Group
1977/08/24 New Adjustment Pin And Valve Seal Used In Fuel Ratio Control
1977/09/28 Changes To The Injection Pump And The Fuel Setting
1977/09/28 Do Not Use Plastic Tubing With Brass Couplings As A Fuel Supply Line
1977/09/28 Stronger Piston Is Used; Piston And Connecting Rod Are Tapered In Area Of Piston Pin
1977/09/28 Use Only The Larger Size Inserts To Make A Repair To Cylinder Block Counterbores For Cylinder Liners
1977/09/28 Use Viscous (Fluid) Type Crankshaft Vibration Damper In Place Of Rubber Type Damper
1977/09/28 Turbocharger Heat Shields Are Stronger
1977/10/12 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
1977/10/12 If The Fuel Setting Dimension Is More Than 7.00 MM, Remove The End Play Of The Camshaft To Make The Fuel Setting
1977/10/12 New Front Housing Has Stronger Boss For Alternator
1977/10/12 Improved Main, Thrust And Connecting Rod Bearings Have Aluminum Alloy With More Strength
1977/10/12 Improved Oversize And Undersize Connecting Rod And Main Bearings With Higher Strength Aluminum Alloy
1977/10/12 Washer Removed From Variable Timing Unit