Iveco Stralis AT/AD. Manual — part 45
Figure 76
SELECTING THE BIG END BEARING SHELLS
(JOURNALS WITH NOMINAL DIAMETER)
There are three markings on the body of the connecting rod
in the position shown in the view from ”A”:
Letter indicating the class of weight:
A
=
3973 to 4003 g.
B
=
4004 to 4034 g.
C
=
4035 to 4065 g.
Number indicating the selection of the diameter of the
big end bearing seat:
1
=
87.000 to 87.010 mm
2
=
87.011 to 87.020 mm
3
=
87.021 to 87.030 mm
Numbers identifying the cap-connecting rod coupling.
1
2
3
The number, indicating the class of diameter of the bearing
shell seat may be 1, 2 o 3.
Determine the type of big end bearing to fit on each journal
by following the indications in the table (Figure 77).
47557
VIEW FROM “A”
STD.
1
2
3
1
2
3
green
green
red
red
red
red
red
red
green
green
green
green
green
green
green
green
red
red
Class
Figure 77
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AT/AD
166
F3A ENGINE
Base - January 2003
Figure 78
green/black
If the journals have been ground, the procedure described so far cannot be applied.
In this case, it is necessary to check (for each of the undersizings) which field of tolerance includes the new diameter of the
crankpins and to mount the bearing shells identified with the relevant table.
-0.127
1
2
3
82.843
82.852
green/black
green/black
green/black
green/black
green/black
green/black
red/black
red/black
green/black
green/black
green/black
red/black
red/black
red/black
red/black
green/black
green/black
82.853
82.862
82.863
82.873
1
2
3
red/black =
mm 2.044 to 2.053
green/black =
mm 2.033 to 2.043
-0.254
1
2
3
82.726
82.735
red
green
green
red
green
green
red
=
mm 2.097 to 2.107
green =
mm 2.108 to 2.117
-0.508
1
2
3
82.472
82.481
red
green
green
red
green
green
red
red
green
red
red
green
82.482
82.492
red
red
green
red
red
green
red
=
mm 2.224 to 2.234
green =
mm 2.235 to 2.244
82.736
82.746
167
S
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F3A ENGINE
SELECTING BIG END BEARING SHELLS (GROUND JOURNALS)
Arrange the bearing shells (1) on the main bearing housings
in the crankcase base (2).
Check the assembly clearance between the main journals of
the crankshaft and their bearings, proceeding as illustrated on
the following pages.
Using the tackle and hook 99360500 (1), mount the
crankshaft (2).
When fitting the gear (1) on the crankshaft (2), heat it for no
longer than 2 hours in an oven at a temperature of 180
°C.
After heating the gear (1), fit it on the shaft by applying a load
of 6000 N to it, positioning it at the distance shown in
Figure 79.
After cooling, the gear must have no axial movement under
a load of 29100 N.
If changing the pin (3), after fitting it on, check it protrudes
from the crankshaft as shown in the figure.
73534
47579
47578
49021
Mount the oil nozzles (2), making the grub screw match the
hole (3) on the crankcase.
Arrange the bearing shells (1) on the main bearing housings.
Check that the toothing of the gear is neither damaged nor
worn; if it is, take it out with an appropriate extractor and
replace it.
540811
Checking main journal assembly
clearance
Figure 79
Figure 80
Figure 81
Figure 82
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F3A ENGINE
Base - January 2003
Replacing the timing gear
and oil pump
- Lubricate the internal screws (1) with UTDM oil and
tighten them with a torque wrench (3) to a torque of
120 Nm, using tool 99395216 (4), to an angle of 90
°,
following the diagram of Figure 85.
Set two journals of the crankshaft (2) parallel to the
longitudinal axis, a section of calibrated wire. Using
appropriate hooks and tackle, mount the crankcase base (1).
60559
47579
47578
47588
60593
Figure 83
Figure 84
Figure 85
Figure 86
Figure 87
- Remove the crankcase base.
The clearance between the main bearings and their journals is
measured by comparing the width taken on by the calibrated
wire (2) at the point of greatest crushing with the graduated
scale on the case (1) containing the calibrated wire.
The numbers on the scale give the clearance of the coupling
in millimetres. If you find the clearance is not as required,
replace the bearing shells and repeat the check.
FRONT SIDE
DIAGRAM OF SEQUENCE FOR TIGHTENING THE SCREWS FIXING THE BOTTOM CRANKCASE BASE
TO THE CRANKCASE
Checking crankshaft end float
α
End float is checked by placing a magnetic dial gauge (2) on
the crankshaft (1), as shown in the figure. If the value obtained
is higher than specified, replace the rear thrust half-bearings
and repeat this check.
169
S
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F3A ENGINE
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