Removal and Disassembly
On 4-cylinder engines, the connecting rod and cap
are stamped for installation in the proper cylinder.
When removing piston assemblies, check the mark-
ing
so
each can be installed in the proper cylinder.
1.
Drain crankcase oil and remove oil base.
2. Remove cylinder heads.
3. Before pushing pistons out, remove ridge at top
of cylinder bore.
4. Remove cap from each connecting rod and push
assembly through top
of
cylinder bore. Replace
cap and bearing inserts in proper assembly.
5.
Using a ring expander, remove rings from each
piston.
6. Remove two retaining rings and push piston pin
from each piston.
Cylinders
ThecylinderwalIsshouId be freeof scratches, pitting
and scuffing. Check each with an inside reading
micrometer for out-of-round and wear. RDJF bore
should measure between 3.4995 inches (88.8873 mm)
and 3.5005 inches (88.9127 mm) and be less than
0.001
inch (0.0243 mm) out-of-round. RDJC bore
should measure between 3.2495 inches (82.537 mm)
and 3.2505 inches (82.563 mm) and be less than
0.001
inch (0.0243 mm) out-of-round.
If necessary, rebore the cylinderto fit the next availa-
ble oversize piston. Pistons and rings are available in
0.005
inch (0.127 mm),
0.010
inch (2.540 mm),
0.020 inch (0.508 mm) 0.030 inch (0.762 mm) and
0.040 inch (1.016 mm) oversize. If the cylinders do
not need refinishing, remove any existing ridges from
the top of the walls with a fine stone.
Pistons:
Clean thoroughly and inspect each piston. Clean the
carbon from the ring grooves and be sure all oil holes
are open. If any piston is badly scored or burred,
loose in the cylinder, has badly worn ring grooves or
otherwise is not in good condition, replace it. See
Figure
55.
Ins fall pistons with valve relief recess
facing the camshaft side of engine
to match valve positions.
Check the clearances 90 degrees from the axis of the
piston pin and just below the oil control ring. Clear-
ance should be
0.0055
inch to 0.0075 inch (0.140 to
0.191 mm). If not, replace the piston and check the
cylinder for possible reconditioning.
CAST !RON
OIL CONTROL
INSTALL
WITH
VENTS
AT
BOTTOM
(AWAY
FROM
CLOSED
END
OF
PISTON)
RINGS PISTON
-I
OIL
CONTROL-^^^^^^^^^
'
'
VENTS
FIGURE
55.
PISTON
RINGS
RINGS
Inspect each ring carefully for fit in the piston
grooves and seating on thecylinderwall. Fit each ring
to the cylinder wall at the bottom of its travel, using a
piston to square the ring in the bore. Check the gap
with a feeler gauge. It should be
0.010
inch to 0.020
inch (0.25 to
0.51
mm). If the gap is too small, file the
butt ends of the rings.
Do
not use rings that need a lot
of filing. They will not seat right on the cylinder walls.
If oversize pistons are used, use the correct oversize
rings.
CONNECTING
RODS
Clean the connecting rods and check each for
defects. Check the connecting rod bushings for
proper clearance with the piston pin. Clearance
should be 0.0002 inch to 0.0007 inch
(0.0051
to
0.018 mm).
If the bushings are excessively worn, press them out
and install one new bushing from each side of the
bushing bore. Press the new bushingsonly until flush
with the sides
of
the rod to leave 1/16 inch to 7/64inch
(1.588 to 2.776lmm) oil groove in the center. See
Figure 56.
PISTON PINS CONNECTING ROD BEARINGS
Each piston pin should be a thumb push fit into its
piston at room temperatures. If the
pin
is excessively
loose, install a new one. If the condition is not cor-
rected, install the next oversize pin. If the piston is
worn enough
so
that the oversize pin will not fit,
replace
it.
oversize precision bearings.
Inspect the connecting rod bearings for burrs,
breaks, pitts and wear. Measure the clearance between
bearings and the crankshaft journal. The clearance
should be 0.0010 inch to 0.0033 inch (0.025 to 0.084
mm). If necessary, replace with new standard or
54
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