Subaru 2002 IMPREZA Service Manual page 1110

MECHANICAL
3. 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 mi-
crometers respectively.
Clearance between the valve guide and valve
stem:
Standard
Intake
0.035 — 0.062 mm (0.0014 — 0.0024 in)
Exhaust
0.040 — 0.067 mm (0.0016 — 0.0026 in)
Limit
0.15 mm (0.0059 in)
2) If the clearance between valve guide and stem
exceeds the limit, replace the valve guide or valve
itself whichever shows greater amount of wear.
See the following procedure for valve guide re-
placement.
Valve guide inner diameter:
6.000 — 6.012 mm (0.2362 — 0.2367 in)
Valve stem outer diameters:
Intake
5.950 — 5.965 mm (0.2343 — 0.2348 in)
Exhaust
5.945 — 5.960 mm (0.2341 — 0.2346 in)
(1) Place the cylinder head on ST1 with the
combustion chamber upward so that valve
guides enter the holes in ST1.
(2) Insert the ST2 into valve guide and press it
down to remove the valve guide.
ST1 498267600 CYLINDER HEAD TABLE
ST2 499767200 VALVE GUIDE REMOVER
CYLINDER HEAD ASSEMBLY
S2M1882A
ME(TURBO)-68
(3) Turn the cylinder head upside down and
place ST as shown in the figure.
ST 498767700 VALVE GUIDE ADJUSTER
(4) Before installing a new valve guide, make
sure that neither scratches nor damages exist
on the inside surface of the valve guide holes in
cylinder head.
(5) Put a new valve guide, coated with sufficient
oil, in cylinder, and insert ST1 into valve guide.
Press in until the valve guide upper end is flush
with the upper surface of ST2.
ST1 499767200 VALVE GUIDE REMOVER
ST2 498267700 VALVE GUIDE ADJUSTER
(6) Check the valve guide protrusion.
Valve guide protrusion: L
12.0 — 12.4 mm (0.472 — 0.488 in)
(7) Ream the inside of valve guide with ST.
Gently rotate the reamer clockwise while press-
ing it lightly into the valve guide, and return it
also rotating clockwise. After reaming, clean the
valve guide to remove chips.
ST 499767400 VALVE GUIDE REAMER
CAUTION:
• Apply engine oil to the reamer when reaming.
• If the inner surface of the valve guide is torn,
the edge of the reamer should be slightly
ground with an oil stone.
• If the inner surface of the valve guide be-
comes lustrous and the reamer does not chips,
use a new reamer or remedy the reamer.
G2M0763
S2M1883A