2
103
E
N
G
IN
E ASS
E
M
B
LY AN
D CO
NTRO
LS
Extraction of valve stem seals from valve stems.
Checking flatness of cylinder head.
VALVE STEM SEAL AND LOWER
STOP WASHER
Should there be excessive oil consumption
or a white-like exhaust smoke which cannot
be blamed on the oil-scraper rings on the
piston, replace the valve stem seals
1
, inten-
ded to prevent excess oil leakage.
It is recommended to replace them every
time the cylinder head is overhauled.
In order to replace them, use needle-nose
pliers to pull them out, being careful not to
nick the valve guide.
Once the valve stem seal is extracted, the
lower cup can be pulled out
2
.
CYLINDER HEAD: CHECKING
CYLINDER HEAD BODY
Check the flatness between the head and
cylinder coupling surfaces.
This can be done using a rectified block and
a thickness gauge by positioning the block
according to the directions shown in the fi-
gure.
The service limit is:
cylinder head flatness service limit:
0.05mm
Check that the state of use of the sliding
zones
A
with the camshafts and
B
of the
camshaft support bearing housing are free
of scratches or signs of meshing.
Clean the oil passages for lubricating the
cylinder head by blowing compressed air
into the holes
C
,
D
and
E
.
2
.17
.5
1
C
B
A
E
D
2
2
.17
.4.3