Improved Exhaust Valve Now Available
Usage:
3406, 3408, 3412 Engines in All Applications
Description of Change: A different method is now used to make the stem and head of the exhaust valve straight. In addition, a different heat treatment is used to prevent damage to the silicon material in the head of the valve. The method used to make the stem and head straight on the former exhaust valve some times caused hard spots and stress in the valve. Because of these stresses, failure of the valve was possible.
Adaptable As: The new 7N2271 Valve is a direct replacement for the former 4N5653 Valve which is canceled.
The new valve was "First Used" as shown in the chart that follows:
Caterpillar Information System:
1977/03/15 Hardened Washers Now Used Between The Bolt Heads And The Engine Front Support To Keep These Bolts Tight
1977/03/15 Changes To Retainer Nut Torque And Assembly Procedures For Turbocharger Compressor Wheels
1977/03/15 Clip Now Used To Hold Coolant Line For The Turbocharger
1977/03/15 Lock Now Available For Connecting Rod Bolt Used In TU-FL0501 Air Compressor
1977/02/28 Improved Shut-Off Solenoids For Engines Equipped With Sleeve Metering Fuel Systems
1977/02/28 List Of Service Publications
1977/02/28 Exhaust Manifold Coupling With A Slip Fit Now Used Instead Of A Coupling With Piston Rings
1977/02/28 Drain All Coolant From Engines Before Shipment For Remanufacturing
1977/02/28 Diesel Fuel Recommendation Expanded
1977/02/28 New 5P7307 Engine Turning Tool Group Fits All Engines
1977/01/28 Improved Crankshaft Main Bearing With Higher Strength Aluminum Alloy
1977/01/28 Low Emission Truck Engines With Exhaust Gas Recirculation (EGR) Systems
1977/03/15 Modification To Holder To Machine Counterbore On Cylinder Block
1977/03/15 Drains In New Fuel Injection Pump Housing And Governor Housing Prevent Possible Corrosion And Freezing Damage
1977/03/15 New Spring Used In Fuel Ratio Control
1977/03/15 Cooling System Orifice Changed For Better Flow Control And Air Removal
1977/04/06 Loose Bolts And/Or Bracket Can Cause Air Compressor Failures
1977/04/06 New Retainer And Improved Housing Keep Water Pump Bearing Tight; Repair For Loosened Bearing
1977/04/06 New Shaft Assemblies Used For Forward And Reverse Clutch And Stronger Nipple Used At Oil Pump
1977/04/06 Use Insert To Repair Bearing Seat In Water Pump Housing
1977/04/06 Coolant Flow Warning System Can Be Adapted To Many Earlier Models
1977/04/06 Revision Of Engine Data Sheet Gives Important Information On Single-Bearing Generators Assembled To Cat Engines
1977/04/06 New Diaphragm Used In Brakesaver Control Valve
1977/04/06 List Of Service Publications