Valve Seats
1) Check valve seats before any other cylinder head service.
Insert valve and hold firmly against valve seat. Measure valve stem
tip-to-cylinder head distance. See Fig. 15. This measurement
determines installed valve height. Subtract measured distance from
minimum specification. See MINIMUM VALVE INSTALLED HEIGHT table.
2) The difference is maximum refacing allowable for valve and
seat. If valve installed height is too low or too high, lifters will
not work correctly. Replace cylinder head assembly.
MINIMUM VALVE INSTALLED HEIGHT
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Application In. (mm)
Intake Valve .......................................... 1.33 (33.9)
Exhaust Valve ......................................... 1.34 (34.1)
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Fig. 15: Measuring Installed Valve Height
Courtesy of Volkswagen United States, Inc.
Valves
Measure valve length, stem diameter and valve margin. If not
within specification, replace valves. Lap valves by hand or replace as
necessary. See VALVES table under ENGINE SPECIFICATIONS.
HYDRAULIC LIFTER TEST
To determine weak or noisy lifter, position camshaft lobe
high point upward. Using a piece of wood, push lifter down. See
Fig. 16. If lifter moves down more than .004" (.10 mm), replace
lifter. If lifter moves less than .004" (.10 mm), lifter is okay.
Repeat procedure for remaining lifters.
CAUTION: If new lifters have been installed, engine must not be
started for 30 minutes. Otherwise, valves may come in contact
with pistons.
Fig. 16: Depressing Lifter
Courtesy of Volkswagen United States, Inc.
