FIG. A.lll/5 CHECKING RUNNING CLEARANCE
OF CRANKSHAFT JOURNALS IN BEARINGS
a.
Arrangement
of
wire for cap Installation;
b. Measure
of
wire flattening after cap removal;
10.
Perfect
circle
plastigage
type
PR·1;
11. Graduated scale stamped on the wire
envelope
CRANKCASE BEARINGS
The thin·shell bearings have
an
anti-friction
metal lining. They require no adjustment but
must be replaced when the working surface is
worn
or
scored beyond the permissible
limits.
Check the clearance with the crankshaft journals
as follows:
Thoroughly clean the journals, bearing shells
and bearing bores with solvent. Use a segment
of
"Perfect Circle Plastigage" type
PR-1
of
the
same length as the bearing cap and place it
lengthwise on the bearing shell about 6 mm.
(1.4
in.)
off
center (Fig. A.lll/5). Install the cap with
plasticgage and torque
to
the value specified in
the "Torque
Specification"
table.
Rock the shaft through a small arc, back and
forth. Remove the cap and measure the wire flat
with the graduated scale (in mm.
or
in.) drawn on
the envelope containing the wire (Fig. A.lll/5).
Remember that:
1.
The flattened wire may
stick
to
the shaft.
2.
The reading is the clearance.
3.
If
one end
of
the wire
is
more flattened than
the other, then taper is present. Measure the
14018
FIG. A.lll/6 INSTALLATION (REMOVAL) OF
THRUST WASHERS
(12)
ON
THE THIRD MAIN
BEARING
(13)
two
ends, the difference being the approx-
imate amount
of
taper.
When assembling the main bearings and their
caps make sure to:
1.
Arrange bearing shells in their original loca-
tions
as they are not interchangeable, and
align lubricating oil grooves.
2.
Fit the thrust washers (Item
12,
Fig. A.lll/6) to
the third bearing (Item
13)
and cap with the
lubricating grooves towards the central shaft
journal shoulders.
3.
The identification figures stamped on the
main bearing caps must be on the crankcase
side stamped with
their
respective bearing
identification marks (Fig. A.lll/7).
4.
Before installing the connecting rod-piston
assemblies,
check
the
end
float
of
crankshaft at the third main bearing (Fig.
A.lll/7).
PISTONS AND RINGS
Standard size and oversized pistons
are
selected
according
to
the measure (Fig. A.lll/8) taken at
50
mm.
off
the skirt base, from two dimensional
classes,
"A"
and
"8",
as reported in the
"Fits
and Tolerances" table.
Engine-
25
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