1990/10/29 Caterpillar

Modification Of 1U7791 Valve Seat Driver{0782,1103}

Usage:

1.1 Liter Family Of Engines

The intake valve seat insert (B) of the 1.1 Liter Engine may not be fully seated when installed with a 1U7791 Valve Seat Driver (A).

During installation of the intake valve seat insert, the end of the valve seat driver may contact the intake port wall. This prevents the insert from being fully seated in the cylinder head insert bore. See Illustration 1.

Illustration 1. Location of possible interference.

To correct this problem, the 1U7791 Valve Seat Driver has to be modified. Modify the valve seat driver to the dimensions and surface textures shown in Illustration 2.

The driver is hardened to Rockwell "C" 43-48. It is recommended that carbide tooling be used during the rework process. When completed, the hardness should be at Rockwell "C" 40-42. There is no need to reharden the driver when done.

NOTE: It is not necessary to remove the driver guide during the modification.

Illustration 2. Modification of valve seat driver.

Caterpillar Information System:

1990/10/29 New Bearing Kits Used In Turbocharger Cartridge Groups{1052,7551}

1990/10/29 Governor Control Motor Polarity May Require A Change{1265,1408,7556}

1990/10/29 New Temperature Regulators Prevent Engine Overheating{1355}

1990/10/29 New CE (Caterpillar Environmental) Family Of Metal-Shell Connectors Used{7553}

1990/10/22 New "On Engine" Adjustment Procedure For 3161 Woodward Governor {1264,0782}

1990/10/22 Increased Capacity Oil Sumps Require Additional Oil And Different Maintenance Interval {1302,1318,7524,7525}

1990/10/22 Front Trunnion Bolts May Come Loose {1153,1154}

1990/10/22 Improved 7C1757 Exhaust Manifold Group {1059}

1990/10/22 Setscrew And Nut Available For Fuel Setting And Injector Synchronization {1257}

1990/10/22 Correct Procedure To Check For Grounds On Woodward 9905 Series, 2301A Control; Correction For Service Manual Module; 2301A Electric Governors (Load Sharing) For Generator Set And Industrial Engines; Form SENR3585-01 {1289}

1990/10/22 Engine Service Training Literature Uses New Form Number {0370,0374}

1990/10/22 New 4C5084 Oil Filter Cutter Replaces Former 6V7905 Filter Cutter {1318,1261,5068}

1990/10/29 New Cylinder Head Gasket And Higher Cylinder Head Bolt Torque{1124,1101}

1990/10/29 Improved 7W7730 Cylinder Head Gasket Provides Better Sealing Capability{1124}

1990/11/05 New Composite Halogen Headlights And Floodlights Available{1429,1434}

1990/11/05 Obsolete Capacitor In VR1 Voltage Regulators{4467}

1990/11/05 New Exhaust Manifold Gasket And Locks Used In Exhaust Manifold Groups{1059}

1990/11/05 New Stronger Exhaust Valve Push Rod Used In Valve Mechanism Groups{1208}

1990/11/05 Some Components Of The 7E3580 Engine Adapter Group For Allison AT545, MT543D, And MT653DRD Transmissions Are Not Serviced By Caterpillar{3279,1013,3009}

1990/11/05 Service Manual SENR3479-04 Available For Troubleshooting Engine Test Procedures{1901,1900}

1990/11/05 New Crankshaft Seal Groups Used{1160,1161,1202}

1990/11/12 New 7X1400 Digital Diagnostic Tool (DDT) Group Available {0782,0785,1900}

1990/11/12 Adjustable Exhaust Bypass Group Used; Provides More Precise Ability To Set Exhaust Pressure {1057}

1990/11/12 New Alternator Drive Pulley Seal Used With New Drive Pulley; Poly-Vee Belt Can Be Installed {1425,1357}