Installation Of Connecting Rod Bearing Inserts; Little End Bushing - Fiat 500L Workshop Manual

tolerance range of .00043 to .00240 inch or less than
.0059 inch the bearing inserts may be used again with-
out any need for regrinding. Should however the
clearance be greater than .0059 inch the inserts must be
renewed, using undersize inserts if the crankpin journals
have been reground.
It should be observed that 'Plastigage PG-1' is suitable
5
for measuring clearances up to .0030 inch so that if
carrying out 3 above produces no flattening of the
'Plastigage' the procedure must be repeated using
'Plastigage PR-1' which enables clearances up to
.0060 inch to be measured.
CRANKSHAFT
CON ROD
FIG 1:30 'Plastigage' position for bearing insert-to-
crankpin journal clearance inspection
GRADUATION SCALE
CLEARANCE
READING
CON ROD BEARING CAP
FIG 1 :31 Checking bearing insert-to-crankpin journal
clearance by comparing width of flattened 'Plastigage'
F500
CALIBRATED STRIP
CON ROD
BEARING CAP
BEARING INSERT
BEARING .INSERT
CALIBRATED
STRIP
REVOLUTION
DIRECTION
FIG 1:32 Connecting rod-piston assembly installation
on engine

Installation of connecting rod bearing inserts:

During reassembly of the big-end bearing inserts the
parts must be thoroughly cleaned and then to reassemble
proceed as follows:
1
Ensure the bearing half to connecting rod surfaces are
perfectly smooth and free of score marks. Under no
circumstances may the bearing surface be reworked.
2
Check that the bearing half inserts are properly seated,
with the locating lugs fitting into their slots: this is
essential to obtain correct bearing clearance.
3 As the circumference of the bearing half is greater than
the seats in connecting rod and cap the bearing must be
fitted so that the projection at each end of the bearing
half is equal.
4
Thoroughly lubricate all parts and tighten the end cap
nuts to a torque wrench setting of 23.9 Ib ft.

Little end bushing:

The small end bush must be a firm fitting in the con-
necting rod and show no signs of deep scoring, scuffing,
ovality or excessive wear.
Should it be considered necessary, the bush may be
reamed using a Fiat expanding reamer U.0307 so that the
bush internal diameter permits an oversize piston pin to be
fitted with a clearance of .00020 to .00063 inch.
To fit a replacement bush proceed as follows:
1 Firmly hold the connecting rod between soft faces in a
vice in such a way that it will not bend when working
on the small-end and using a suitably sized drift, remove
the old bush.
2 Use Fiat tool A.60155 or a suitably sized drift and care-
fully install the new bush which must be an interference
fit of between .0011 to .0036 inch.
3 A small slot must be cut in the bush to correspond with
the groove machined at the top of the connecting rod
so ensuring good lubrication between the bush and
piston pin.
PISTON SLOT
CAMSHAFT
CONNECTING
ROD NUMBER
23