44,000...44,025
10,1
43--- 8
48,500...48,525
11
±0,1
Cylinder Head
3---3
F. Changing valve seat rings
Exhaust and inlet valves are fitted with separate valve seat
rings. If the sealing surface is damaged so badly that it cannot
be repaired with machining, the seat ring should be changed.
1. Grind the valve head on a discarded valve so that it sits
down in the valve seat. Fit the valve and weld it in place in the
seat. Cool with water.
2. Turn the cylinder head over and knock out the valve and
seat.
EXHAUST
INLET
3. Clean the valve seat location and check dimensions. Cool
the new seat ring in liquid nitrogen until it stops bubbling, or
alternatively place it in dry ice.
4. Fit the seat with a suitable drift. Machine the seat.
Note!
Where necessary, standard size seats can be replaced
by inserts with a larger outer diameter. See technical data,
point
cylinder head
.
G. Grinding valves
In order to ensure that there is a proper seal around the
valves, there is a difference in the sealing surface angles.
Thus there is a very narrow sealing surface which seals effec-
tively even after prolonged running.
A
B
43--- 9
C
A
B
C
Inlet
35
˚
---20’
35
˚
+20’
0,7±0,05 mm (max. 2,20 mm)
Exhaust 45
˚
---20’
45
˚
+20’
0,6±0,05 mm (max. 2,20 mm)
1. Grind the damaged valve disc with a valve refacer. Adjust
angles to
45
˚
---20’
for exhaust valves and
35
˚
---20’
for inlet
valves.
2. If the edge of the valve head is less than
1,5 mm
after it has
been ground, or if the valve stem is bent, the valve should be
discarded.
3. If necessary, grind the end of the valve stem.
4. Lap the valves with lapping paste and check the contact
surface with marking paint.
5. Clean the cylinder head and valves of any remaining lap-
ping paste.
H. Fitting valves
1. Check the valve springs for straightness, length and ten-
sion using a spring tester. Compare with specifications.
2. Lubricate the valve stems and fit the valves in the correct
order in the cylinder.
3. Fit the springs, spring guides and valve keepers with the
aid of a lever for compressing valve springs, 9101 66200.
4. Tap the end of the valve stems lightly after fitting the valve
in order to ensure that they are secure.
