reading. When the run out on the adja-
cent journals is in the same direction,
the difference must not exceed 0.003" to-
tal indicator reading. If the runout limit
is greater than 0.002" at the No. 2 and 4
journal, or 0.004" at the No. 3 journal,
the crankshaft must be replaced.
Measure all of the main and connecting
rod bearing journals (see Figure 11B-73
on page 11B-49). Measure the journals
at several places on the circumference so
that taper, out-of-round and bearing
clearances can be determined. If the
crankshaft is worn so that the maximum
journal-to-bearing shell clearance (with
new shells) exceeds 0.0044", the crank-
Figure 11B-70. Ridging of Crankshaft
shaft must be reground. Measurements
of the crankshaft should be accurate to
Slight ridges on the crankshaft oil seal
the nearest 0.0002". Also, if the journal
contact surface may be cleaned up with
taper of a used crankshaft exceeds
0.0015" or the out-of-round is greater
emery cloth and crocus cloth in the same
manner as detailed for the crankshaft
than 0.001", the crankshaft must be re-
ground.
journals. If the crankshaft cannot be
cleaned up satisfactorily, the oil seal may
be repositioned in the flywheel housing
Also measure the crankshaft thrust sur-
faces
(see
Figure
11B-75
on
as outlined in this subsection.
Check the crankshaft thrust surfaces for
excessive wear or grooving. If only
slightly worn, the surfaces may be
I n s p e c t i o n for Cracks
dressed with a stone. Otherwise will
be necessary to regrind the thrust sur-
Carefully check the crankshaft for crack
faces.
which start at an oil hole and follow the
journal surface at an angle of 45 to the
axis. Any crankshaft with such cracks
Check the oil pump drive gear and the
crankshaft timing gear for worn or
must be rejected. Several methods of
chipped teeth. Replace the gears, if ne-
determining the presence of minute
cessary.
cracks not visible to the eye are outlined
below.
Check the crankshaft dowel extension.
Dowels extend 1/2" from the crankshaft.
MAGNETIC PARTICLE METHOD.
The
Check to make sure the dowels DO NOT
part is magnetized and then covered with
extend more than 1/2", otherwise inter-
a fine magnetic powder or solution.
Flaws, such as cracks, form a small local
ference with the torque converter fly-
wheel will result.
magnet which causes the magnetic parti-
cles in the powder or solution to gather
there, effectively marking the crack.
Inspect the crankshaft for cracks as out-
lined under Inspection for Cracks.
The crankshaft must be de-magnetized
after the test.
FLUORESCENT MAGNETIC PARTICLE
C r a n k s h a f t Measurements
METHOD. This method is similar to the
magnetic particle method, but is more
Support the crankshaft on its front and
sensitive since it employs magnetic parti-
rear journals on V-blocks or in a lathe
cles which are fluorescent and glow un-
and check the alignment at the adjacent
der "black light". Very fine, cracks that
intermediate main journals with a dial in-
may be missed under the first method,
dicator.
especially on discolored or dark
surfaces, will be disclosed under the
When the runout on the adjacent journals
"black light".
is in opposite directions, the sum must
not
exceed
0.003"
totaI
indicator
Engine (Less Major Assemblies)
11B-47
