ARMY TM 9-2815-254-24
AIR FORCE TO 38G1-94-2
Hold gear to be checked and adjoining gear stationary.
Move gear tooth side to side in backlash. Record indicated backlash TIR. Standard TIR is 0.004-0.007
in. (0.10 to 0.17 mm), with a limit of 0.012 in. (0.30 mm).
If TIR exceeds limit, replace gear.
FIGURE 3-100. Measuring Timing Gear Backlash
Measure idler gear end play as follows:
(1) Insert feeler gage between idler gear (3, FIGURE 3-101) and thrust collar (2) and measure gap.
(2) Standard end play (gap) is 0.003 in. (0.07 mm), with a limit of 0.008 in. (0.2 mm)
(3) If end play exceeds limit, replace thrust collar (2).
Remove two screws (1) securing thrust collar (2), idler gear (3) and shaft (4). Remove gear (3) from shaft
Remove fuel injection pump, refer to paragraph 3-11.1.
m. Remove cylinder head, refer to paragraph 3-27.1.