MANIFOLD GP-EXHAUST COMBUSTION 3365043 - Caterpillar

After the dial indicator has been correctly set, place the indicator with the attached timing fixture on the injector follower surface. The roller on the lifter assembly must be on the base circle of the cam lobe and not on any other portion of the cam lobe. The correct position of the lifter assembly roller is shown in the illustration. Refer to the appropriate Service Manual for the procedure to correctly position the cam follower.
If the injector is correctly timed, the dial indicator will show a reading of 0.00 .20 mm. If the dial indicator gives a reading of + .21 mm or greater, this means the stem of the indicator has moved toward the dial indicator and Dimension (A) is shorter than it should be. Since the injector plunger is directly connected to the injector follower, a reading of + .21 mm means the injector plunger has moved too far down the injector barrel toward the combustion chamber. Timing will be too far advanced in this case.
If the dial reading is - .21 mm or less, Dimension (A) is longer than it should be. Negative numbers become less in value as they get larger (farther away from zero). Thus - .22 is less than - .21, - .23 is less than - .22, and so forth. The plunger is too far up the injector barrel and away from the combustion chamber. Timing will be too far retarded in this case.
To correct these last two conditions it will be necessary to loosen the locknut on the adjustment screw and turn the adjustment screw until 0.00 mm is indicated on the dial face. Tighten the locknut to a torque of 70 15 N m (50 11 lb ft) and check Dimension (A) again.
Service Reporting
If the timing dimension needs to be measured and recorded for service reports before any changes are made to the dimension, proceed as follows:
1. Use the 6V3117 Set Gauge and the correct dimensions from the chart to set the dial indicator to the desired setting as previously described. Remember, if the dial indicator has been correctly set up off-engine in this manner, the indicator reading on-engine will always be 0.00 .20 mm on a correctly timed injector.2. Compute the actual timing dimension (Dimension A) as measured on-engine. To do this, the dial indicator reading must be either added to or subtracted from the specified fuel timing dimension. Subtract the dial indicator reading from the specified dimension if the indicator reading is a positive number. Add the reading to the specified dimension if the reading is negative. EXAMPLE 1. The specified timing dimension is 87.64 mm. The on-engine dial indicator reading is +0.27 mm. In this case the actual timing dimension is .27 mm subtracted from 87.64 mm. This equals 87.37 mm. Injector timing is too far advanced.
EXAMPLE 2. The specified timing dimension is 87.00 mm. The on-engine dial indicator reading is -0.49 mm. In this case, the actual timing dimension is the