Subaru 2009 IMPREZA, Service Manual

Page: 1132 / 3619

ME(H4DOTC)-74
Cylinder Head
MECHANICAL
4. INTAKE AND EXHAUST VALVE
1) Inspect the flange of valve and valve stem, and
replace the valve with a new part if damaged, worn,
deformed, or if dimension “H” in the figure is out-
side of the specified limit.
Head edge thickness H:
Standard
Intake (A)
1.0 — 1.4 mm (0.039 — 0.055 in)
Exhaust (B)
1.3 — 1.7 mm (0.051 — 0.067 in)
2) Put a small amount of grinding compound on the
valve seat surface, and lap the valve and valve seat
surface. Replace with a new valve oil seal after lap-
ping.
NOTE:
It is possible to differentiate between the intake
valve and the exhaust valve by their overall length.
Valve overall length:
Intake
104.4 mm (4.110 in)
Exhaust
104.65 mm (4.1201 in)
5. VALVE SPRING
1) Check the valve springs for damage, free length,
and tension. Replace the valve spring if it is not
within the standard value presented in the table.
2) To measure the squareness of the valve spring,
stand the valve spring on a surface plate and mea-
sure its deflection at the top of the valve spring us-
ing a try square.
ME-00758
H
H
(B)
(A)
Free length mm (in) 47.32 (1.863)
Tension/spring
height
N (kgf, lb)/mm (in)
Set
205 — 235 (20.9 — 24.0,
46.1 — 52.8)/36.0 (1.417)
Lift
426 — 490 (43.4 — 50.0,
95.8 — 110)/26.50 (1.041)
Squareness
2.5°, 2.1 mm (0.083 in) or
less
ME-00283