DETROIT DIESEL 53
Camshaft and Bearings 1.7.2
face is scored or if the thrust washers are worn
Inspection
excessively, replace the washers. New thrust washers
are .208" to .210" thick.
Soak the camshaft in clean fuel oil. Then, run a wire
brush through the oil gallery to remove any foreign
Also, examine the surfaces which the thrust washers
material or sludge. Clean the exterior of the camshaft
contact; if these surfaces are scratched but not severely
and blow out the oil gallery and the oil holes with
scored, smooth them down with an oil stone. If the
compressed air. Clean the camshaft bearings and
score marks are too deep to be removed, or if parts are
related parts with fuel oil and dry them with compressed
badly worn, use new parts.
air.
The clearance between new shafts and new bearings is
Inspect the cams and journals for wear or scoring. If the
.0045" to .006", or a maximum of .008" with worn parts.
cams are scored, inspect the cam rollers as outlined in
Excessive clearance between the shafts and the
Section 1.2.1.
bearings will cause low oil pressure and excessive
backlash between the gears.
Examine both faces of the thrust washers. If either
Bearings are available in .010" and .020" undersize for
Engine
Bearing
Dimension
use with worn or reground shafts.
Location
Minimum
Maximum
6V
End
2.385"
2.386"
Oversize camshaft bearings are available in sets, .010"
6V
Intermediate
2.375u
2.376"
oversize on the outside diameter, to permit reuse of a
cylinder block having one or more scored block bearing
TABLE 1
bores. To use the oversize bearings, the camshaft
block bores must be carefully line-bored (machined) to
the dimensions shown in Table 1.
Fig. 4. - Installing Intermediate Camshaft Bearing
1972 General Motors Corp.
February, 1972
SEC. 1.7.2 Page 3
