Volkswagen Type II Transporter 1200 Series Shop Manual page 18

12-Engine
TO REF ACE VALVES AND VALVE SEATS
(1) The valve seats in the cylinder head should be
refaced with a 45° seat cutter when badly pitted or burnt.
NOTE: Only sufficient metal should be removed with the
seat cutter to obtain a concentric seating surface clear of
pits or other damage.
(2) Using a 75° cutter chamfer the lower edge of the
valve seat face.
(3) Using a 15° cutter chamfer the upper edge of the
valve seat face.
NOTE: It is essential that the correct seat width is obtained
f l -
COTTERS
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RETAINER
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SEAL
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"
SPRING
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VALVE
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Valve and Spring Components.
18
during the refacing procedure. The inlet seat width should
be . 051" -. 063" and the exhaust seat width should be
.067" -.079". The seat widths can be na"owed by
operations ( 2) and ( 3) and increased by operation (1 ). The
outer edge of the upper 15° chamfer should not exceed the
outer diameter of the seat insert.
(4) Pitted or burnt valves should be. refaced with a
valve refacing machine provided the pitting or burning of
the seat face is not extensive when the valve should be
replaced.
NOTE: Valve seat widths for both inlet and exhaust valves
should be the same as specified earlier for the cylinder head
valve seat inserts.
(5) Correctly refaced valves and valve seats should
require very little lapping to obtain accurate seating. Ensure
that the valve is frequently lifted clear of the seat and
rotated during the lapping operation to avoid grooving the
seat faces.
(6) With the grinding compound thoroughly cleaned
from the valves and seats, check the fit of the valves to the
valve seats.
(7) Smear the valve face with be.aring blue and insert
the valve into position, using light hand pressure rotate the
valve a quarter turn only.
(8) Remove the vaive and inspect the faces. A correctly
seated valve should have evenly transferred the blue to the
valve seat.
TO ASSEMBLE AND INSTAL
Assembly and installation is a reversal of the
dismantling and removal procedures with attention to the
following points:
(1) Ensure that all grinding compound has been
cleaned from the components.
(2) Check that the valve retaining collets are correctly
seated in the spring seat and valve grooves.
(3) Check that the cylinder head holding studs are tight
in the block.
(4) Instal a new gasket between the cylinder head and
the cylinder shoulder.
NOTE: Gaskets are not fitted between the cylinder head
and the top edge of the cylinder.
(5) Fit new seals to the push rod tubes and instal them
with the tube seam facing upwards. If necessary stretch the
tubes to 7.11" -7.16" to ensure positive sealing, but use
care to avoid cracking the tubes.
(6) Place the cylinder head in position over the studs,
smear the cylinder head securing nuts with graphite paste
and instal them on the studs after first fitting the nut
washers.