DETROIT DIESEL 53
1.7.2 Camshaft and Bearings
NOTE: If a steel rod is not available, remove the remaining plug as
outlined in Steps "a" through "g".
Inspection
Soak the camshaft in clean fuel oil. Then, run a wire brush through the oil gallery to remove any foreign
material or sludge. Clean the exterior of the camshaft and blow out the oil gallery and the oil holes with
compressed air. Clean the camshaft bearings and related parts with fuel oil and dry them with compressed air.
Inspect the cams and journals for wear or scoring. If the cams are scored, inspect the cam rollers as outlined in
Check the runout at the center bearing with the camshaft mounted on the end bearing surfaces. Run
out should not exceed .002 ".
CAMSHAFT AND BALANCE SHAFT CYLINDER
BLOCK BORE MACHINING CHART
Engine
Bearing
Dimension
Location
Minimum
Maximum
3
End
2.385"
2.386"
3
Intermediate *
2.375"
2.376"
TABLE 1
Examine both faces of the thrust washers. If either face is scored or if the thrust washers are worn excessively,
replace the washers. New thrust washers are .208 " to .210 " thick.
Also, examine the surfaces which the thrust washers contact; if these surfaces are scratched but not severely
scored, smooth them down with an oil stone. If the score marks are too deep to be removed, or if parts are
badly worn, use new parts.
The clearance between new shafts and new bearings is .0045 " to .006 ", or a maximum of .008 " with worn
parts. Excessive clearance between the shafts and the bearings will cause low oil pressure and excessive
backlash between the gears.
Bearings are available in .010 " and .020 " undersize for use with worn or reground shafts.
Oversize camshaft and balance shaft bearings are available in sets, .010" oversize on the outside diameter,
to permit reuse of a cylinder block having one or more scored block bearing bores. To use the oversize
bearings. the camshaft and balance shaft block bores must be carefully line-bored (machined) to the
dimensions shown in Table I.
Figure 4. Installing Intermediate Camshaft Bearing
August, 1972 SEC. 1.7.2 Page 3
