Ask a Heavy Equipment Repair Mechanic for Answers ASAP
Rotate the accessory drive in the direction of engine rotation. The accessory drive will rotate clockwise, when looking at the front of the engine. Align the "A" or "1-6 VS" mark on the accessory drive pulley with the pointer on the gear cover. Note: It is important to adjust the injector first before adjusting the valves on a cylinder when using the OBC overhead set procedure. Check the valve rocker levers on cylinder #1 to see if both valves are closed. Both the intake and exhaust valves are closed when both rocker levers are loose. If both valves are not closed, then rotate the accessory drive a complete revolution and align the "A" or "1-6 VS" mark again. If the valve rocker lever adjusting screws have been loosened and not yet adjusted, watch the valve push tubes as the engine rolls towards the mark. Both valve push tubes will have moved to the downward (or valve closed) position if the engine is on the correct stroke.
Outer Base Circle (OBC) Injector and Valve Adjustment Sequence
Bar Engine in Direction of Rotation
Start Advance to Advance to Advance to Advance to Advance to
1 5 3 6 2 4
Firing Order: 1 - 5 - 3 - 6 - 2 - 4
Refer to the engine model and CPL for the correct injector rocker lever adjusting screw torque value.
Use a dial type torque wrench to tighten the injector lever adjusting screws to the specified torque. If the screw causes chattering during setting, repair the screw and lever as required. Hold the torque wrench in a position that allows you to look in a direct line at the dial to insure that you are reading it accurately. The torque wrench must be calibrated and have a range of 150 in. lbs. On non-brake engines, if the injector screw is a slotted type. Be careful that the screw driver does not slip out of the slot. These screws can be (and should be) replaced with the hexagon type. Hold the adjusting screw and torque the lock nut to 40 ft lbs on a New Big Cam IV and 88 Big Cam IV's and to 50 ft lbs on N14 models. After setting the injector on a given cylinder, set the valves on the same cylinder. Notice that the OBC method requires new valve settings for the New Big Cam IV and the 88 Big Cam IV engines. Hold the adjusting screw and torque the locknut to 54 ft lbs on New Big Cam IV and 88 Big Cam IV's and to 50 ft lbs on N14 models. Advance the accessory drive pulley to the next mark and adjust the injector and valves. Continue through two revolutions of the engine to complete all six cylinders.
Bar in Direction
A or 1-6VS B or 2-5VS C or 3-4VS A or 1-6VS B or 2-5VS C or 3-4VS
5 3 6 2 4 1
Firing Order: 1 - 5 - 3 - 6 - 2 - 4 Right Hand Rotation
In setting the C-Brake, the OBC or IBC sequence can be used. However, to eliminate confusion, it will be easier to use the same sequence that was used to set the overhead.
Tighten the rocker lever shaft cap screws.