3
113
E
N
G
IN
E ASS
E
M
B
LY AN
D CO
NTRO
LS
Taking the valve out, the paint will be missing in the
contact zone. Its width must not be greater than the
following service limit:
Width service limit of valve seat contact zone:
1,9 mm.
The contact zone can principally take on three diffe-
rent appearances, as shown in the figure:
A
- correct;
B
- incorrect (contact face damaged);
C
- incorrect (uneven seat width).
Also check the correct positioning of the contact area.
It must be neither higher (case
D
) or lower (case
E
).
Should the incorrect conditions described above oc-
cur, the valve seats must be rectified, respecting the
conditions carried in the following drawing.
If the valve seats are beyond recovery, replace the
cylinder head.
A
D
E
B
C
Valve-seat contact conditions: A) Correct; B) Incorrect - contact face damaged-; C) Incorrect - uneven width-.
Positioning of contact area: D) too high; E) too low
Geometric features of valves seats.
