Test Fixture
cord around the periphery of the gear
several times.
Attach the other end of
the cord to spring scale, J 8129 (see
page
11B-110).
Main-
tain a straight, steady pull on the cord
and scale, 90 to the axis of the hub,
Figure 11B-165. Fixture for Testing
and note the pull, in pounds and ounces,
required to start the gear rotating.
B e a r i n g Pre-Load
Make several checks to obtain an average
reading.
If the pull is within 1/2 lb. mi-
hub by tilting, wobbling or shaking the
n i m u m t o 4 I b s . maximum and does not
gear.
fluctuate more than 2 Ibs, 11 ounces, the
idler gear and bearing assembly are sat-
If the mating crankshaft and camshaft
isfactory for use.
gears are not already mounted on the
engine, the torque required to rotate the
If the crankshaft and camshaft gears are
idler gear may be checked by mounting
mounted on
the engine, a
the idler gear in position on the engine,
suitable
fixture, which may be held in a vise, can
using a steel plate 4" square (pre-load
be made as shown in Figure 11B-165.
test plate) against the hub and cone as
outlined below:
a 1/2"-13x 2-3/4" bolt and a plain washer
are used with a 1/2"-13 nut and plain
1. Mount the idler gear assembly on the
washer for mounting. One of the plates
engine.
is used to take the place of the flywheel
2. Install the center bolt and washer
housing, the other two plates, the cylin-
der block.
Engine mounted conditions
through the gear hub and into the cylin-
are simulated by tightening the nut to
Tighten the bolt to 80-90
der block.
80-90 lb-ft (108-122 Nm) torque and
tightening the three plate-to-hub attach-
ing bolts to 25-40 lb-ft (34-54 Nm)
3. Place steel plate (lower plate shown in
torque.
against
hub
and
Insert
three 3/8"-16 bolts
bearing.
Check the pre-load as follows:
through the plate and thread them into
Tighten the bolts to 24-40
the hub.
A. Attach the plates (two upper plates
gear with 1/2"-13 bolt, washer and
4. Tie one end of a piece of lintless 1/8"
n u t s a s shown i n F i g u r e 1 1 B - 7 6 5 .
cord around a 1/8" round piece of wood
the
bolt
to
80-90
lb-ft
Tighten
Place the wood
(or soft metal stock).
(108-122 Nm) torque.
between the teeth of gear, then wrap the
Engine (Less Major Assemblies)