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3.17.4.1 SPRINGS
Each valve is retained by a spring. The length of the-
se springs must be checked while they are loose:
service limit = 42,5mm
Should the springs be shorter, have them replaced.
3.17.4.2 VALVE GUIDES, VALVES AND SEATS
Make sure that the valve guides are free from
scratches or any type of nicks. To check the correct
diameter, introduce the gauge in the valve guides
from the side of the combustion chamber (code
006140180 000)
. If the gauge can enter, the valve
guide must be replaced at a rectification workshop.
To this purpose, keep to the data carried in the dra-
wing.
Remember that if replacing the valve guides, the
seats of the valves must be repassed as described
later on.
Brush the valve mushroom head thoroughly and
degrease the entire valve.
Make sure that the valve stems are free from
scratches or any type of nicks. Measure the diame-
ter of the valve stems, making sure it is not less
than the service limit:
Valve stem diameter service limit: 5,95mm
If it is, replace the valve. Play between the valve and
the valve guide must not be greater than the limit
carried below:
Play limit between valve and valve guide:
0,08mm
If play is greater, first try to replace the valve. Should play
still not be within the aforementioned limits, intervene
on the valve guide.Check the valve mushroom head
zone, making sure that the area of contact with the seat
is not dented: if so, replace the valve.
Check the state of wear of the valve seats and the sealing
surface. In order to do this, apply a light layer of Prussian
blue paint on the contact zone of the valve with the seat.
Then insert the guide valve until you press it against the
seat and turn it on its own axis.
Measuring length of free spring.
Reference dimensions for processing and fitting
valve guide.
