Iveco Stralis AT/AD. Manual — part 44
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To obtain the required assembly clearances, the main and big end bearing shells need to be selected as described
hereunder.
This operation makes it possible to identify the most suitable bearing shells for each of the journals (the bearing shells, if necessary,
can have different classes from one journal to another).
red
red/black
green
green/black
STD
1.970 to 1.980
1.981 to 1.990
+0.127
2.033 to 2.043
2.044 to 2.053
+0.254
2.097 to 2.107
2.108 to 2.117
+0.508
2.224 to 2.234
2.235 to 2.244
Depending on the thickness, the bearing shells are selected
in classes of tolerance marked by a coloured sign (red-green
— red/black — green/black).
The following tables give the specifications of the main and
big end bearing shells available as spares in the standard sizes
(STD) and in the permissible oversizes (+0.127, +0.254,
+0.508).
* Fitted in production only and not supplied as spares
Figure 72
yellow*
yellow/black*
1.991 to 2.000
red
red/black
green
green/black
STD
2.965 to 2.974
2.975 to 2.984
+0.127
3.028 to 3.037
3.038 to 3.047
+0.254
2.097 to 2.107
2.108 to 2.117
+0.508
2.224 to 2.234
2.235 to 2.244
yellow*
yellow/black*
2.985 to 2.995
2.054 to 2.063
3.048 to 3.058
S
TRALIS
AT/AD
162
F3A ENGINE
Base - January 2003
Main journals and crankpins: determining the class of diameter of the journals.
Three sets of numbers are marked on the crankshaft in the position shown by the arrow (Figure 73 at top):
- The first number, of five digits, is the part number of the shaft.
- Under this number, on the left, a set of six digits refers to the crankpins and is preceded by a single digit showing the status
of the journals (1 = STD, 2 = -0.127), the other six digits, taken singly, give the class of diameter of each of the crankpins
they refer to (Figure 73 at top).
- The set of seven digits, on the right, refers to the main journals and is preceded by a single digit: the single digit shows the
status of the journals (1 = STD, 2 = -0.127), the other seven digits, taken singly, give the class of diameter of each of the
main journals they refer to (Figure 73 at bottom).
Figure 73
82.970 to 82.979
82.980 to 82.989
82.990 to 83.000
CLASS
CRANKPIN
NOMINAL DIAMETER
92.970 to 92.979
92.980 to 92.989
92.990 to 93.000
CLASS
MAIN JOURNALS
NOMINAL DIAMETER
163
S
TRALIS
AT/AD
F3A ENGINE
DEFINING THE CLASS OF DIAMETER OF THE MAIN JOURNALS AND CRANKPINS (Journals with nominal diameter)
After reading off the data, for each of the main journals, on the crankcase and crankshaft, you choose the type of bearing shells
to use according to the following table:
STD.
1
2
3
1
2
3
green
green
red
red
red
red
green
green
green
green
red
red
green
green
green
green
green
green
Figure 74
S
TRALIS
AT/AD
164
F3A ENGINE
Base - January 2003
green/black
If the journals have been ground, the procedure described so far cannot be applied.
In this case, it is necessary to check that the new diameter of the journals is as shown in the table and to mount the only type
of bearing shell envisaged for the relevant undersizing.
-0.127
1
2
3
99.843
99.852
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
99.853
99.862
99.863
99.873
1
2
3
red/black =
mm 3.028 to 3.037
green/black =
mm 3.028 to 3.047
-0.254
1
2
3
99.726
99.746
red
red
red
red
red
red
red =
mm 3.237 to 3.247
-0.508
1
2
3
93.468
93.508
red
red
red
red
red
red
red =
mm 3.219 to 3.229
Figure 75
165
S
TRALIS
AT/AD
F3A ENGINE
SELECTING THE MAIN BEARING SHELLS (GROUND JOURNALS)
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