Skoda Octavia 1996 Service Manual page 75

OCTAVIA
Edition 05.97
S00.5105.51.20
Cylinder Head/Valve Gear
Procedure
Reworking can be carried out on a machine or
by hand. It is essential to comply with the
following conditions:
l Wear limit of valve guides must not exceed
maximum permissible dimension ⇒ page
15-22.
l Use NAC milling cutter with carbide metal
blades (min. 90 HRC).
K Reworking valve seats with NAC hand
milling cutter
- Place cylinder head on a felt base and secure
against turning.
- Match diameter of guide drift to diameter of
valve guide.
Valve guide
Exhaust valve
- Match diameter of milling cutter to diameter
of valve seat.
Valve seat
Inlet valve
Exhaust valve
K Sequence of milling
1. Machine valve seat with 90° milling cutter
until a proper contact pattern is achieved
(do not exceed maximum permissible
reworking dimension).
2. Mill top correction angle with 120° milling
cutter until valve seat diameter „a" or valve
seat width „c" (⇒ page 15-24) is achieved.
∅ ∅ ∅ ∅ ∅
Inlet valve
Milling cutter
90° mm
41
34
15
∅ ∅ ∅ ∅
∅
∅ ∅ ∅ ∅ ∅
Guide drift mm
7.0 -0.01
Milling cutter
120° mm
41
34
¡ ¢ £ ¡
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