GUARD AS 9W8174 - Caterpillar

Removal Procedure
Start By:
Remove the front cover.
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Do not turn the crankshaft or the camshaft while the camshaft gear is removed. If the front gear group is not correctly timed during installation, interference can occur between the pistons and the valves, resulting in damage to the engine.
Illustration 1 g01010536
Position the No. 1 piston at the top center of the compression stroke. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston".
Verify that the timing mark on camshaft gear (1) is aligned with Timing Mark (X) on front housing (3).
Remove bolts (2) and remove camshaft gear (1). Installation Procedure
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Do not turn the crankshaft or the camshaft while the camshaft gear is removed. If the front gear group is not correctly timed during installation, interference can occur between the pistons and the valves, resulting in damage to the engine.
Install camshaft gear (1) in the reverse order of the removal.
Illustration 2 g02748956
Tighten the bolts (2) to a torque of 240 40 N m (177 30 lb ft). Tighten using the above illustrated sequence. Tighten the bolts illustrated as 1 and 2 an additional 240 40 N m (177 30 lb ft).
Check the backlash between the camshaft gear and the adjustable idler gear. The backlash should be 0.356 0.254 mm (0.014 0.010 inch). Refer to Testing and Adjusting, "Gear Group (Front) - Time" for the backlash adjustment procedure.