1.7.3
DETROIT DIESEL 53
CAMSHAFT AND BALANCE SHAFT GEARS
The camshaft and balance shaft gears on an In-line
engine
are located at the flywheel end of the engine
and mesh with each other and run at the same speed
as the crankshaft
Since the camshaft and balance shaft gears on In-line
engines
must be in time with each other, timing marks are
stamped on the rim of each gear. Also, since these two
gears as a unit must be in time with the crankshaft,
timing marks are located on the idler and crankshaft
gears (refer to Section 1.7.1).
Each gear is keyed to its respective shaft and held
securely against the shoulder on the shaft by a nut. A
gear nut retainer, with a double hexagon hole in the
center, fits over the nut on some engines. The retainer
is attached to the gear by bolts threaded into tapped
holes in the gear.
cylinder In-line engines,
three
On the
external weights are attached to the rear face of each
gear.
The weights are important
in maintaining perfect engine balance.
Fig. 1 Removing Camshaft Gear
Inspection
When new service gears are used on an In-line engine,
Clean the gears with fuel oil and dry them with
the external weights on the old
compressed air. Then examine the gear teeth for
gears must be `transferred to the new gears. If the
evidence of scoring, pitting and wear. Replace the
weights are transferred to new gears, tighten the bolts
gears if necessary.
to 45-50 lb-ft torque.
Examine both faces of the camshaft and balance shaft
thrust washer and, if either face is worn or scored,
replace the washer. Also examine the surface on the
Remove Camshaft and Balance Shaft Gears
camshaft and balance shaft which the thrust washer
contacts. If this surface is scratched. but not severely
1. Remove the camshaft and the balance shaft from
scored, smooth it up with a tine oil stone.
the engine as outlined in Section 1.7.2.
2. Place the camshaft and gear assembly in an arbor
press with the gear suitably supported as shown in
Install Camshaft and Balance Shaft Gears
Fig. 1.
1. Note the letters stamped on the end of the camshaft
3. Place a wood block under the lower end of the
which signify the engine models in which a camshaft
camshaft so the threads will not be damaged when the
may be used. The letters on the timing gear end of the
shaft is pressed from the gear.
camshaft must correspond with the engine model of
the particular engine being assembled. Refer to the
4. Place a short piece of 3/4" O.D. brass rod between
front of this manual for engine model identification.
the end of the camshaft and the ram of the press; then
force the camshaft out of the camshaft gear.
2. Place the rear camshaft spacer over the timing gear
end of the camshaft and install the Woodruff key.
5. Remove the thrust washer, Woodruff key and spacer
from the camshaft.
3. Lubricate the thrust washer with clean engine oil
and place the thrust washer over the gear end of the
6. Remove the gear from the balance shaft in a similar
camshaft and the spacer
manner.
July. 1970 SEC. 1.7.3 Page 1
