INJECTOR AS-FUEL 3990541 - Caterpillar

434-3868 Plate - Used to hold the gear segment tool in place and prevent the segment tool from rotation when checking backlash of cam gear.
Illustration 2 g03870106Setting Backlash for Camshaft and Adjustable Idler Gear
Note: The rocker arm bolts must be loosened to remove preload from the camshaft.
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Front cover is removed.
With the front cover removed, remove bolts (3), plate (2), and adjustable idler gear (1).
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Loosen one bolt and two nuts (4) that secure the stub shaft. Remove the remaining three nuts. The one bolt and two nuts (4) can still be accessed when the gear segment tool is installed.
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(5) Timing marks
(6) 374-3473 Gear Gauge
With the flywheel pinned at TDC for cylinder one, align timing marks (5).
Install the cam gear backlash tool onto the stub shaft, as shown. Both sides of the gear segment tool should be engaged with the corresponding gear, as shown. Hand tighten the one bolt and two nuts enough so that slight resistance is felt if the stub shaft is rotated.
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The 434-3868 Plate can be installed to hold the gear segment tool in place.
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Measure the backlash between camshaft gear (2) and gear segment tool (3). When the gear segment tool is held stationary, the backlash between the gears is 0.356 0.254 mm (0.014 0.010 inch). Lightly tap the stub shaft with a soft mallet to move the gear segment tool closer or further away to the cam gear as necessary. This movement will increase or decrease the amount of backlash.
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Once the proper backlash is obtained, tighten the nuts and the bolt (4) to a torque of 55 10 N m (41 7 lb ft).
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Remove the cam gear backlash tool.
Clean the studs with a wire brush to remove any old thread lock compound for the three nuts and washers removed in Step 2.
Apply Loctite 242 to the studs.
Install the 3 nuts and washers that were removed and torque to 55 10 N m (41 7 lb ft).
Remove the bolt, two nuts, and two washers that were tightened in Step 6.
Clean the bolt and two studs of any old thread lock compound using a wire brush.
Apply Loctite 242 to the bolt and the two studs.
Install the bolt and two nuts with washers. Torque the bolt and nuts to 55 10 N m (41 7 lb ft).
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Install idler gear (1). Verify that the correct amount of backlash is still correct. The mark on the camshaft gear should still align with the mark on the front housing.
Install plate (2). Before installing bolts (3), clean the bolts with a wire brush to remove the old thread lock compound. Apply Loctite 242 to the threads of the bolts and install the bolts. Then, tighten to the proper torque.
Install the front cover. Refer to Disassembly and Assembly, "Housing (Front) - Install".