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6
6.2.5 Dimensional check and overhaul of crankshaft
1. Wash the crankshaft thoroughly using suitable
detergent.
2. Introduce a pipe cleaner into the lubrication ducts to
remove any residual dirt.
3. Blow compressed air into the points indicated to free
the ducts from oil.
4. Check the surfaces of the main journals and crank
pins for wear and tear to see whether grinding is
necessary.
5. Using a micrometer, measure the diameter of the main
journals (A1) and crank pins (B1).
6. Using a dial indicator, measure the inside diameters
of the crankshaft (A2) and connecting rod (B2) half
bearings
Important
• Crankshaft half bearings cannot be replaced
separately.
• If the crankshaft needs to be ground, establish the
diameters of the connecting rod and crank pins,
in order to choose the matching measurements
available of connecting rod and half bearing spare
parts (see "Table of diameters of connecting rods
and half bearings").
• When grinding the crankshaft it is possible to
downrate the crankshaft and connecting rod pins by
0,25 mm and 0,50 mm.
• When grinding the crankshaft it is also necessary
to consider grinding the sides (shoulder) to be able
to choose uprated ring replacements (see "Table of
uprated shoulder half-rings").
• Protect the contact surfaces with lubricant oil, to
prevent them from rusting.
46
OVERHAULS AND TUNING
Service Manual LDW FOCS 502 automotive _ cod. ED0053027270 - 3° ed_rev. 02
52
Table of diameters of connecting rods and half bearings
Wear and
Dimensions
Réf.
tear limit
(mm)
A1
47,984÷48,000
A 2
48,022÷48,058
B 1
39,894÷40,000
B 2
40,020÷40,035
Table of diameters of connecting rods and half bearings
Wear and
Dimensions
Réf.
tear limit
(mm)
A1
47,984÷48,000
A 2
48,025÷48,071
B 1
39,984÷40,000
B 2
40,021÷40,050
Table of uprated shoulder half-rings
Half-rings
Standard
22,787÷22,920
1° increase
22,987÷23,120
2° increase
23,087÷23,220
3° increase
23,187÷23,320
53
Clearance (mm)
(mm)
47,900
A 2 - A 1 =
0,032÷0,016
48,055
39,900
B 2 - B 1 =
0,021÷0,066
40,100
PROGRESS
Clearance (mm)
(mm)
47,95
A 2 - A 1 =
0,025÷0,087
48,1
39,95
B 2 - B 1 =
0,021÷0,066
40,08
Dimensions (mm)
A
B
23,050÷23,100
23,250÷23,300
23,350÷23,400
23,450÷23,500
Max
clear.
(mm)
0,200
0,130
Max
clear.
(mm)
0,12
0,10
Clearance
C = A-B
0,130÷0,313
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