AUDI A8 1999 D2 / 1.G AHA ATQ Engines Valve Gear Repair Manual

15-53

Valve seats, refacing


Notes:

Only reface valve seats enough until a perfect
contact pattern is obtained.
Before refacing, calculate the maximum
refacing dimension.
If refaced dimension is exceeded, hydraulic
valve lifter function is no longer guaranteed and
cylinder head must be replaced.

Calculating maximum allowable refacing
dimension

- Insert valve and press firmly against valve
seat.

Note:
If valve is replaced during repair, use a new
valve for measurement.

- Measure distance between end of valve stem and top surface of
cylinder head (four-valve head shown).
- Calculate maximum allowable refacing dimension using distance
measured and minimum dimension.
Pa
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gear, servicin
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11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE03.15.1

15-54

Minimum dimensions
Outer intake
valve Center intake
valve Exhaust valve
32.2 mm
(1.268 in.) 33.2 mm
(1.307 in.) 33.0 mm (1.299
in.)
The measured distance minus the minimum
dimension equals the maximum permissible
refacing dimension.

Example
Outer intake valve
Measured distance 33.0 mm (1.299
in.)
Minimum dimension - 32.2 mm (1.268
in.)
Maximum permissible refacing
dimension = 0.8 mm (0.031
in.)

Note:
If the measured distance is less than the
minimum dimension, repeat the measurement
with new valves, or replace the cylinder head.
Pa
ge 62 of 62 Valve
gear, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE03.15.1