Porsche 1989 944 S2, Руководство по ремонту

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15
Engine, Cylinder Head, Valve Drive 944
Replacing the valve guides
1. Clean and inspect the cylinder head. It is
inexpedient to replace the valve guides
in
cylinder heads where remachining is no
longer possible on the valve seats or
sealing areas.
2. Lay the cylinder head on the ejection
base.
3. Press out the valve guides from the
camshaft side to the combustionchamber
side with a press.
87/921
4. Measure the bores in cylinder with an
internat measuring caliper.
87/919
5. Machine the SP valve guide Part No.
944
104 327 51 (outer diameter 11.26 mm)
accordingly.
The pressing must amount to 0.06 - 0.8
mm
for intake and exhaust valve guides
Example
Bore in the cylinder head measures
11.020 mm. Machine the outside diameter of
the SP valve guide accordingly to 11.080 or
11.10 mm.
Note
A 1 mm thick washer must always be placed
on cylinder-head face before installing the
valve guide.
6. Heat the cylinder head up to 170 °C
(338°
F). Apply a film of tallow tothe valve
guides.
Position with a light knock, align and.
from
the camshaftside, press into the cylinder
head as far as the stop with aplunger.
Attention
The temperature of 170 °C (338 °F). must
only be maintainedfor a maximum of 90
minutes.
15 - 128 Replacing the valve guides
Printed in Germany - XVII, 1988