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REPAIR INSTRUCTIONS
CAMSHAFT GEAR INSTALLATION
The camshaft gear is shrink-fit onto the camshaft.
To install the gear, it must be heated in an oven to
425
°
F (204
°
C). Do not attempt to heat the gear
with a welding torch as this method will not
provide even heating and could cause weakening
of the metal.
An oven is the preferred method for heating the
camshaft gear. However, an industrial grade hot
plate can be used as an alternative to the oven.
When using a hot plate, temperature sticks or a
thermocouple must be used to determine gear
temperature. The hot plate, temperature sticks
and thermocouple are available through any
industrial supply company.
The camshaft gear is a “long-life” part that should
be reused providing it is not damaged.
When installing the camshaft gear, use only the
heat method procedure below for both new or
used parts. Do not use a press to install the gear.
HEAT METHOD — CAMSHAFT GEAR
INSTALLATION
Refer to Figure 162.
1. Using a suitable contact-type cleaner that
dries rapidly and leaves no residue,
thoroughly clean the camshaft and gear.
The camshaft and gear must be grease- and oil-
free to ensure a good shrink-fit.
2. Install the key (4) into the camshaft keyway.
It may be necessary to tap the key with a
soft metal hammer to ensure proper seating
of the key.
Some engines use a straight key while others use
an offset key positioned to the right or left
depending on the engine model. If an offset key is
used, be sure the key is properly positioned for
the engine model. Refer to the appropriate MACK
Engine Tune-up Specifications for the correct key
offset.
3. Install a new camshaft captured thrust
washer (2) on the camshaft.
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