1977/01/28 Caterpillar

Same Valve Camshaft Assembly Used On Direct Injection Engines Now Used On Engines That Have Precombustion Chambers

Usage:

3406 Truck, Industrial and Marine Engines Equipped with Precombustion Chambers

Description of Change: The valve camshaft assembly used currently on 3406 Engines equipped with a direct injection fuel system is now also used on the above engines.

Adaptable As: The new 6N4991 Camshaft Assembly is a direct replacement for the former 6N1405 Camshaft Assembly which is canceled.

The 6N4991 Camshaft Assembly was first used on 3406 Engines with direct injection, starting with Serial Numbers 92U3187 and 90U514. The 6N4991 Camshaft Assembly was first used on 3406 Engines with precombustion chambers, starting with Serial Numbers 92U7387, 90U2496 and 91U549.

INSTALLATION: When the 6N4991 Camshaft Assembly is installed, it is our recommendation that you install new 6N4589 Valve Lifters and 6N6872 Spring Clips.

Caterpillar Information System:

1977/01/28 New Water Temperature Regulator Has A Closer Fit At The Valve Seat To Keep Leakage At A Minimum

1977/01/28 Lightening Holes Not Drilled In Some Crankshafts

1977/01/28 New Tie Bars Improve Stability Of The Fuel Injection Test Bench

1977/01/28 Removal Of Bolts With Metal Locks Easier With New Sockets

1977/01/28 What Is In The Microfilm Engine Bills Of Material?

1977/01/28 When Oil Mixes With Engine Coolant, Clean Cooling System And Install New Water Pump Seals

1977/01/28 New Cylinder Liners

1977/01/28 Exhaust Valve Guides With A Counterbore Are Now Available

1977/01/28 Adapter For Disassembly And Assembly Of Turbocharger Cartridge

1977/01/28 Spring Washer Keeps Bolts Tight In Aftercooler Housing

1977/01/28 List Of Service Publications

1977/01/28 Coupling With A Slip Fit Now Used At Turbocharger Exhaust Outlet Instead Of Coupling With Piston Rings

1977/01/28 Improved Main And Connecting Rod Bearings Have Aluminum Alloy With More Strength

1977/01/28 Low Emission Truck Engines With Exhaust Gas Recirculation (EGR) Systems

1977/01/28 Improved Crankshaft Main Bearing With Higher Strength Aluminum Alloy

1977/02/28 New 5P7307 Engine Turning Tool Group Fits All Engines

1977/02/28 Diesel Fuel Recommendation Expanded

1977/02/28 Drain All Coolant From Engines Before Shipment For Remanufacturing

1977/02/28 Exhaust Manifold Coupling With A Slip Fit Now Used Instead Of A Coupling With Piston Rings

1977/02/28 List Of Service Publications

1977/02/28 Improved Shut-Off Solenoids For Engines Equipped With Sleeve Metering Fuel Systems

1977/03/15 Lock Now Available For Connecting Rod Bolt Used In TU-FL0501 Air Compressor

1977/03/15 Clip Now Used To Hold Coolant Line For The Turbocharger

1977/03/15 Changes To Retainer Nut Torque And Assembly Procedures For Turbocharger Compressor Wheels