Iveco EuroCargo (12 to 26 t). Manual — part 20
70325
70326
18625
18882
70327
Figure 138
Figure 139
Figure 140
Figure 141
Figure 142
The rated thickness A for the cylinder head is 105
± 0.25 mm,
max. metal removal shall not exceed thickness B by 0.13 mm.
540662
VALVES
INTAKE AND EXHAUST VALVE MAIN DATA
Remove carbon deposits from valves using the proper metal
brush.
Check that the valves show no signs of seizing, scoring or
cracking.
Regrind the valve seats, if required, using tool 99305018 and
removing as less material as possible.
Check the valve stem (1) using a micrometer (2), it shall be
6.970
± 6.999.
Use a magnetic base dial gauge (1) set as shown in the figure,
the assembling clearance shall be 0.052
± 0.092 mm.
Turn the valve (2) and check that the centering error is not
exceeding 0.03 mm.
!
After grinding, check valve sinking. Regrind the valve
seats, if required, to obtain the specified value.
Removing carbon deposits, checking and
grinding valves
Checking clearance between valve stem and
valve guide and valve centering
INTAKE
VALVE
EXHAUST
VALVE
E
URO
C
ARGO
T
ECTOR
12-26 t
70
ENGINE F4 AE 0481
Base - February 2003
EXHAUST
79457
70330
85486
Figure 143
Figure 144
Use a bore dial gauge to measure the inside diameter of the
valve guides, the read value shall comply with the value
shown in the figure.
Check the valve seats (2). If slight scoring or burnout is found,
regrind seats using tool 99305018 (1) according to the angle
values shown in Figure 145.
VALVE SEATS
Regrinding — replacing the valve seats
VALVE SEAT MAIN DATA
INTAKE
EXHAUST
INTAKE
Figure 145
E
URO
C
ARGO
T
ECTOR
12-26 t
ENGINE F4 AE 0481
71
Base - February 2003
VALVE GUIDE
70333
70332
Figure 146
Figure 147
Should valve seats be not reset just by regrinding, replace
them with the spare ones. Use tool 99305018 (Figure 144)
to remove as much material as possible from the valve seats
(take care not to damage the cylinder head) until they can
be extracted from the cylinder head using a punch.
After regrinding, check that valve (3) sinking value is the
specified one by using the base 99370415 (2) and the dial
gauge 99395603 (1).
Heat the cylinder head to 80
° - 100°C and using the proper
beater, fit the new valve seats, previously cooled, into the
cylinder head.
Use tool 99305018 to regrind the valve seats according to
the values shown in Figure 145.
MAIN DATA CONCERNING THE SEATS ON THE CYLINDER HEAD
EXHAUST
INTAKE
E
URO
C
ARGO
T
ECTOR
12-26 t
72
ENGINE F4 AE 0481
Base - February 2003
Check cleanness of cylinder head and engine block coupling
surface.
Take care not to foul the cylinder head gasket.
Set the cylinder head gasket (1) with the marking “TOP” (1)
facing the head.
The arrow shows the point where the gasket thickness is
given.
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70334
770321
70335
Figure 148
Figure 149
Figure 150
Figure 151
MAIN DATA TO CHECK INTAKE AND EXHAUST
VALVE SPRINGS
Before refitting use tool 99305047 to check spring flexibility.
Compare load and elastic deformation data with those of the
new springs shown in the following table.
FITTING CYLINDER HEAD
Lubricate the valve stems (1) and fit them into the relevant
valve guides according to the position marked at removal.
Fit the sealing rings (2 and 3) on the valve guide.
Position on the cylinder head: the spring (4), the upper cap
(3); use tool 99360268 (1) to compress the spring (4) and
lock the parts to the valve (5) by the cotters (2).
!
Sealing rings (2) for intake valves are yellow and
sealing rings (3) for exhaust valves are green.
Refitting the cylinder head
!
Before reusing the cylinder head fastening screws
check whether they are free from damages or
distortions, otherwise replace.
E
URO
C
ARGO
T
ECTOR
12-26 t
ENGINE F4 AE 0481
73
Base - February 2003
VALVE SPRINGS
Height
Under a load of
mm
N
H
47.75
Free
H1
35.33
P1
339.8
± 19
H2
25.2
P2
741
± 39
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