PLATE AS 2268410 - Caterpillar

The Torque Rise Curve With Correct And Incorrect Dual Slopes
A typical torque rise curve with dual slopes for 777B and 785 Trucks is shown in Illustration 1.
Illustration 1. The dual slopes refer to the two different slopes that are controlled by the torque rise cam.This procedure describes how to position the torque rise cam to obtain the correct fuel setting and engine rpm.
Illustration 2 shows different effects for adjusting the torque rise cam. This procedure will define the upper part of the torque rise curve (shaded line) and explain how to position this line so it intersects the specified Full Load Point. The dashed torque rise lines in Illustration 2 represent a governor with a torque rise cam that has a dual slope, but is incorrectly adjusted.
Illustration 2. Effects of adjusting the torque rise cam.Adjustment Procedure
1. Look in the microfiche for Vehicle (Captive) Engine Fuel Specifications or on the engine information plate to find the correct full torque fuel setting and full load fuel setting.2. Remove alternator and bracket from right side of the front drive housing. If you are checking full load point, go to Step 3. If you are changing or replacing the torque rise cam, make a preliminary setting of the cam according to the procedure in the referenced service manual module on Page 36.3. Make Load Test on Vehicle to define three points on upper part of torque rise curve. a. With engine stopped, install dial indicator and set at zero as per Steps 1 through 5, Pages 31 and 32 of the referenced service manual module. This dial indicator will be used to read fuel linkage position.b. Remove synchronizing pin and install the 8T2819 Linkage Position Indicator in its place. See Illustration 3. Hold the fuel linkage against the fuel setting screw by turning the shaft shown in Illustration 4. Record the full torque fuel setting (dial indicator reading).c. Connect the 6V4060 Set Point Indicator with the 6V2100 Multitach. Follow Steps 1 through 3 on Page 14 of Special Instruction SEHS7931-02. Connect the 1P7446 Cable to the 8T2819 Linkage Position Indicator.
Illustration 3. Installation of linkage indicator and dial indicator for fuel linkage.d. Adjust 8T2819 Linkage Position Indicator as follows (see Illustration 4): d1. Turn the governor shaft so the dial indicator reads 0.5 mm less than the full torque fuel setting.d2. Turn the plastic nut of the indicator in or out until the lug light of the set point indicator just comes on.d3. Tighten the setscrews in the indicator to lock the plastic nut in position.
Illustration 4. Tooling adjustments.e. Measure the point where the linkage position indicator is set. Listen for an indication of contact closure and observe the dial indicator as the governor is moved in the "Fuel On" direction. Record the dial indicator reading.f. Recheck the fuel setting recorded in Step 3b to make sure the dial indicator has not moved out of position. If the fuel setting changes by more than 0.1 mm, recheck the zero setting of the dial