Skoda OCTAVIA MK1 Service Manual page 83

Reworking valve seats with NAC milling
cutter
Place cylinder head on a felt base and
–
secure to prevent it from turning.
Match diameter of guide drift to diameter
–
of valve guide.
Valve guide
Inlet valve
Exhaust valve
– Match diameter of milling cutter to diameter of valve seat.
Valve seat
Inlet valve
Exhaust valve
Milling sequence
1. Mill valve seat with 90° milling tool
until until a perfect contact pattern is
-
achieved. (Do not exceed maximum
permissible reworking dimension!)
2. Initially mill top correction angle with
120° milling cutter until the valve seat
-
diameter "a" or valve seat width "c" is
achieved → Anchor.
Ø Milling cutter 90° mm
41
34
Ø Guide drift in mm
7,0 -0,01
Ø Milling cutter 120° mm
83
41
34