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44
FIAT· 850 PASSENGER CARS
Fig. 83 - Securing connecting rod bearing caps.
1. Torque wrench.• 2. Con rod bearing cap.
- Place a piece of calibrated wire on journal.
- Fit
connecting
rod bearing caps and draw
up cap screws with 25.3 It.lbs (3.5 kgm ) of torque
(fig.
63).
- Remove caps and determine the amount of
clearance comparing the
width
of the flattened
e Plastigage» with the graduations on the envelope
(fig.
64).
If
clearance proves to be within the tolerance
range of .0010" to .0028" (0.026 to 0.071 rom) or
not
in
excess of
.004" (0.10
mm) wear
limit,
bear-
ing
can still be used with crankpins unaltered
in
diameter.
Conversely
if
clearance is greater than above
figures, replace rod bearings
by
undersizes (see
table) and grind crankpins as outlined on page 46
and to the values tabulated hereafter.
SERVICE NOTE· Early type connecting rod bear-
ings shown in fig. 58 can be safely replaced by
the late type. In case the connecting rod is to be
renewed, install late type connecting rod and
bearings.
CRANKPIN DIAMETERS
Undersizes
Standard
.01/1
.02/1
.03"
.04"
(0.254 mrn)
(0.508 mrn)
(0.762 mrn)
(1.016 mrn)
-.
1.5742/1
1.5642"
1.5542/1
1.5442"
1.5342/1
(39.985 mrn) (39.731 mrn) (39.477 mm) (39.223mm) (38.969 mm)
1.5750/1
1.5650"
1.5550/1
1.5450"
1.5350/1
(40.005 rom) (39.751 rom) (39.497 mm) (39.243 nun) (38.989mm)
CONNECTING ROD BEARING INSERT
THICKNESSES
Undersizes
Standard
.01/1
.02"
.03"
.04"
(0.254 rom)
(0.508 mm)
(0.762 mm)
(1.016 rom)
.7114"
.8114"
.9114"
1.0114"
1.1114"
(1.807 nun)
(2.061 nun)
(2.315 mm)
(2.569 mm)
(2.823 mrn)
.7134"
.8138"
.9138"
1.0138"
1.1138"
(1.813 mm)
(2.067 mrn)
(2.321 rom)
(2.575 rom)
(2.829 nun)
Fig. 64 - Comparing the width of the flattened
«
PlasUgage»
with the envelope graduation scale to check connecting rod
bearing Insert-to-journal clearance.
1. Con rod bearing cap. - 2. Bearing Insert.· 3.
(I
Plastigage» wire.-
4. Envelope with graduation scale .• 5. Clearance reading.
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