Chevrolet 10 series 1973, Overhaul Manual

Page: 161 / 522

6 -2 0 ENGINE
Fig. 4 0 —M easuring Gauging Plastic
.001", interference between the bearing and
journal will result in rapid bearing failure. If
the flattened gauging plastic tapers toward
the middle or ends, there is a difference in
clearance indicating taper, low spot or other
irregularity of the bearing or journal. Be sure
to measure the journal with a micrometer if
the flattened gauging plastic indicates more
than .001" difference.
6. If the bearing clearance is within specifications, the
bearing insert is satisfactory. If the clearance is not
within specifications, replace the insert. Always
replace both upper and lower insert as a unit.
NOTE: If a new bearing cap is being
installed and clearance is less than .001",
inspect for burrs or nicks; if none are found
then install shims as required.
7. A standard, .001" or .002" undersize bearing may
produce the proper clearance. If not, it will be
necessary to regrind the crankshaft journal for use
with the next undersize bearing.
8. Proceed to the next bearing. After all bearings have
been checked rotate the crankshaft to see that there
is no excessive drag.
9. Measure crankshaft end play (see specifications) by
forcing the crankshaft to the extreme front
position. Measure at the front end of the rear main
bearing with a feeler guage (fig. 41).
10. Install a new rear main bearing oil seal in the
cylinder block and main bearing cap.
Fig. 4 1 —M easuring C ra n k s h a ft End Play
Replacement
NOTE: Main bearings may be replaced with
or without removing the crankshaft.
With Crankshaft Removal
1. Remove and inspect the crankshaft.
2. Remove the main bearings from the cylinder block
and main bearing caps.
3. Coat bearing surfaces of new, correct size, main
bearings with oil and install in the cylinder block
and main bearing caps.
4. Install the crankshaft.
Without Crankshaft Removal
1. With oil pan, oil pump and spark plugs removed,
remove cap on main bearing requiring replacement
and remove bearing from cap.
2. On the In-Line engine crankshaft, the rear main
journal has no oil hole. Replace the rear main
bearing upper half as follows:
a. Use a small drift punch and hammer to start the
upper bearing half rotating out of block.
b. Use a pair of pliers (with taped jaws) to hold
the bearing thrust surface to the oil slinger and
rotate the crankshaft to remove bearing (fig 42).
c. Oil new selected size upper bearing and insert
plain (unnotched) end between crankshaft and
indented or notched side of block.
d. Use pliers as in removing to rotate bearing into
place. The last 1/4 movement may be done by
OVERHAUL MANUAL