Subaru 2002 IMPREZA Service Manual page 1109

1) Installation of valve spring and valve:
(1) Coat the stem of each valve with engine oil
and insert the valve into valve guide.
CAUTION:
When inserting the valve into valve guide, use
special care not to damage the oil seal lip.
(2) Set the cylinder head on ST1.
(3) Install the valve spring and retainer using
ST2.
ST1 498267600 CYLINDER HEAD TABLE
ST2 499718000 VALVE SPRING REMOVER
CAUTION:
Be sure to install the valve springs with their
close-coiled end facing the seat on the cylinder
head.
(4) Compress the valve spring, and then fit the
valve spring retainer key.
(5) After installing, tap the valve spring retainers
lightly with wooden hammer for better seating.
2) Apply oil to the surface of the valve lifter and
valve shim.
3) Install the valve lifter and valve shim.
E: INSPECTION
1. CYLINDER HEAD
1) Make sure that no crack or other damage exists.
In addition to visual inspection, inspect the impor-
tant areas by means of red check.
2) Measure the warping of the cylinder head sur-
face that mates with crankcase by using a straight
edge (A) and thickness gauge (B).
If the warping exceeds 0.05 mm (0.0020 in), re-
grind the surface with a surface grinder.
Warping limit:
0.05 mm (0.0020 in)
Grinding limit:
0.3 mm (0.012 in)
Standard height of cylinder head:
127.5 mm (5.02 in)
CYLINDER HEAD ASSEMBLY
S2M1881A
ME(TURBO)-67
CAUTION:
Uneven torque for the cylinder head nuts can
cause warping. When reassembling, pay spe-
cial attention to the torque so as to tighten
evenly.
2. VALVE SEAT
Inspect the intake and exhaust valve seats, and
then correct the contact surfaces with valve seat
cutter if they are defective or when valve guides are
replaced.
Valve seat width: W
Intake
Standard
1.0 mm (0.039 in)
Limit
1.7 mm (0.067 in)
Exhaust
Standard
1.5 mm (0.059 in)
Limit
2.2 mm (0.087 in)
MECHANICAL
S2M1840A
G2M0761