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Measuring length of free spring.
Reference dimensions for processing and fitting
valve guide.
3.17.4.1
SPRINGS
Each valve is retained by a spring. The length of
these springs must be checked while they are
loose:
service limit = 42,5mm
Should the springs be shorter, have them re
-
placed.
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 cor
-
rect diameter, introduce the gauge in the valve
guides from the side of the combustion cham
-
ber (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
drawing.
Remember that if replacing the valve guides,
the seats of the valves must be repassed as de
-
scribed 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 dia
-
meter 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, in
-
tervene on the valve guide.Check the valve mushro
-
om 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 se
-
aling 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.