Figure 5-28. Idler Gear and Hub.
Tap back the locking tabs and unscrew the two idler hub
securing setscrews (1, Appendix F, Figure 56).
Remove setscrews (1), idler gear (15, Appendix F, Figure 58),
and hub (4, Appendix F, Figure 56) (see Figure 5-28).
Clean and thoroughly inspect the idler gear and hub for signs of
excessive wear, cracks, pitting, or other damage. Ensure that
oil passages in hub and idler gear are clear.
Idler Gear and Hub Installation (see Appendix F, Figure 56 and 58).
Hold the idler gear (15, Appendix F, Figure 58) in position with the timing marks correctly aligned.
Insert the hub (4, Appendix F, Figure 56) (see Figure 5-29) so that the holes in the hub and the cylinder
block are aligned. Secure with two setscrews (1).
Clearance Is provided in the setscrew holes of the Idler gear hub to provide the
necessary backlash adjustment for the timing gears.
Using the adjustable idler gear, backlash between both crankshaft gear/idler gear should be set within
0.0015-0.0025 in. (0.038-0.064 mm) with the gears held together to take up the effect of bearing
clearance. Check backlash with feeler gages (see Figure 5-30).
Figure 5-29. Idler Gear Installation .
Figure 5-30. Gaging Backlash.
When the backlash has been correctly set, torque the idler hub setscrews (1) to 31 lb.-ft. (42 N
Check the idler gear end float (see Figure 5-31). The limits are 0.003-0.008 in. (0.076-0.203 mm).
When correctly set, the timing gears should appear as shown In Figure 5-32.
Install the timing case cover (see c above).