DETROIT DIESEL 53
1.7.5
CRANKSHAFT TIMING GEAR
The crankshaft gear is keyed and pressed onto the
crankshaft and drives the camshaft gear
through an idler gear. Refer to Fig, 2. under General
Description.
Since camshaft gears, must be in time with the
crankshaft gear, timing marks are located on the rim of
the Idler gear with corresponding marks stamped on the
crankshaft gear, and camshaft gears (6V engine). Refer
to Section 1.7.1.
Remove Crankshaft Timing Gear
The crankshaft timing gear may be removed with the
crankshaft in or out of the cylinder block.
1. Attach bar type puller J 4871 to the crankshaft gear
with three long bolts or hooks, flat washers and nuts
through the holes in the gear as shown in Fig. 1.
Fig. 2. - Installing Crankshaft Timing Gear With
2. Turn the center screw of the puller to pull the
Installer J 7557
crankshaft gear off the crankshaft.
or damaged. Also, check the other gears in the gear
Inspection
train.
Wash the gear in clean fuel oil and inspect the teeth for
Install Crankshaft Timing Gear
wear, pitting or scoring. Replace the gear if worn
1. If removed, install the Woodruff key in the keyway
in the crankshaft.
2. Start the timing gear over the end of the crankshaft
with the timing marks on the outer rim of the gear facing
out and the keyway in the gear in alignment with the
Woodruff key in the crankshaft.
3. Place a heavy hammer against the head of the bolt
in the front end of the crankshaft. Place installer J 7557
against the rear face of the timing gear and drive the
gear up against the shoulder on the crankshaft as shown
in Fig. 2.
4. Check the gear backlash. The specified backlash is
Fig. 1 - Removing Crankshaft Timing Gear
.003"-005" with new gears or a maximum of .008" with
With Puller J 4871
used gears.
1970 General Motors Corp.
July, 1970
SEC. 1.7.5 Page 1
