SHIM PACK 6P7767 - Caterpillar

All Machines Powered By 3406E EnginesReference: Service Manual Module, SENR5578-01, Systems Operation, Testing and Adjusting, Page 75, "Static Check Of The Timing Gear Position".Reports indicate that retiming the 3406E machine engines may occasionally be difficult. It is very important that the timing mark on the cam drive gear assembly be correctly aligned with the timing mark on the top of the front cover housing. The Electronic Control Module will not allow a successful timing event if the engine is more than 4 degrees out of time. Just being one tooth off location with the cam drive gear assembly can result in the engine being up to 7.5 degrees out of time.
Timing Aid Procedure
With Front Cover Removed (Exposing All Timing Marks)
Locations of timing marks (1), (2), (5) (6), tapped hole (3) and dowel rod (4).1. Pin time the flywheel. (Number 1 piston at TDC of its compression stroke).2. Make sure timing mark (6) on the crankshaft gear is aligned with timing mark (5) on the cluster idler gear.3. Install the cam drive gear while aligning the timing mark (2) on the cam drive gear with the timing mark (1) at the top of the front housing. Tighten the bolts that hold the cam drive gear finger tight. The timing mark (2) on the cam drive gear may be up to 1/2 tooth out of alignment with the cast mark (1) on the timing gear housing.4. Remove the plug from the tapped hole (3).5. Insert a piece of 7.92 mm (.312 in) diameter dowel rod, or a 5/16 inch bolt (4), with a minimum length of 76 mm (3 in) into the tapped hole (3). The dowel rod or bolt (4) should fit loosely (up to 3.5 degrees movement of the gear, measured at the chopper teeth diameter) between the chopper teeth. (The chopper teeth are the reference for the speed timing sensor). The dowel rod or bolt (4) will verify that the cam drive gear assembly is in the correct position. Tighten the bolts that hold the cam drive gear in position.6. Remove the dowel rod or bolt (4). Install the plug in the tapped hole (3).7. Attempt the timing calibration as shown in the Service Manual.