CRANKSHAFT, MAIN BEARINGS, FLYWHEEL & CRANKCASE
Fitting New Main Bearing Caps...
Replacement main bearing caps, available for service,
require the face and sides of the caps be modified to the
dimensions of the old cap to assure a perfect fit in the
Modify the caps as follows:
Place a drill rod or a new drill of any size from 6
to 13 mm (1/4 to 1/2 in.) in the bore of the OLD
caps. Measure the distance from the face of the
cap (1, Fig. 25) to the drill rod shank with a
depth gauge as shown and record the reading.
Figure 25. - Measuring Dimension "E"
Surface "D" main bearing cap face
Measure the diameter of the drill rod shank with a
micrometer and add this reading to the one taken with
the depth gauge, to derive dimension "E" in Fig. 25.
NOTE: If the cap being replaced is broken and
dimension "E" cannot be determined, use one of the
other caps to measure "E". Install and torque the
cap before continuing.
Mill or grind surface "D" (1, Fig. 25) of the NEW
cap to dimension "E" plus 0.05 mm (0.002 in.).
NOTE: 0.05 mm (0.002 in.) is added to dimension "E"
to allow enough stock for a finish cut on surface "D"
after the cap and bearing have been fitted to the
NOTE: The Bearing Cap must be located on its
machined side when grinding surface "D" to hold
Clamp the OLD bearing cap to a surface plate
(2, Fig. 26).
Place a drill rod (1, Fig. 26) of any size from 6 to
13 mm (1/4 to 1/2 inch) on the inside of the cap
(against notched side).Measure this distance
with a micrometer as shown in Fig. 26 and
record the reading.
Figure 26. - Measuring Dimension "A"
Measure the diameter of -the drill rod shank and
add this reading to the reading taken in step 4
above. This will be dimension "A".
Measure dimension "A" of the NEW bearing cap
in the same manner as described in steps 2, 4
and 5 above.
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