Subaru XT 1988 Service Manual page 238

2-3 ENGINE
10) Using VALVE SPRING PRESS ASSY (899724100), com-
press the valve spring and remove the valve spring retainer key_
Remove each valve and valve spring_
Mark each valve to prevent confusion.
Fig. 179
VALVE SPRING
PRESS ASSY
(899724100)
INSPECTION
CYLINDER HEAD
L2-1343
1) Make sure that no crack or other damage exists. In ad-
dition to visual inspection, inspect important areas by means
of red check.
2) Measure the warping of the cylinder head surface that
mates with cylinder block by using a straight edge and thick-
ness gauge.
If the warping exceeds 0.075 mm (0.0030 in), regrind the sur-
face with a surface grinder.
Warping limit:
0.075 mm (0.0030 in)
Grinding limit:
0.3 mm (0.012 in)
Thickness gauge
Fig_ 180
L2-1344
82
3) Inspect intake and exhaust valve seats, and correct the
contact surfaces with valve seat cutter if they are defective or
when valve guides are replaced.
W (contacting width):
Intake
1.2 - 1.8 mm (0.047 - 0.071 in)
Exhaust
1.5 - 2.0 mm (0.059 - 0.079 in)
Wear limit of valve seat (measured in
direction of valve axis):
0.5 mm (0.020 in) for both intake and exhaust valves
A5-052
Fig. 181
VALVE GUIDE
1) Check the clearance between valve guide and stem. The
clearance can be checked by measuring the outside diameter of
valve stem and the inside diameter of valve guide with outside
and inside micrometers respectively.
Specifications for valve stem and valve guide
Intake
0.035 - 0.065 mm
Standard clearance
(0.0014 - 0.0026 in)
between valve guide
and valve stem
Exhaust
0.040 - 0.070 mm
(0.0016 - 0.0028 in)
Limit of clearance between
0.15 mm (0.0059 in)
valve guide and valve stem
Standard inside diameter of 7.000 - 7.015 mm
valve guide
(0.2756 - 0.2762 in)
Intake
6.950 - 6.965 mm
Standard diameter
(0.2736 - 0.2742 in)
of valve stem
6.945 - 6.960 mm
Exhaust
(0.2734 - 0.2740 in)