Valve & Valve Shim

WARNING: Metallic sodium is encapsulated in the exhaust valve. Metallic sodium is a strong alkaline material and thus prone to serious chemical reaction. When handling or disposing of the valve, be sure to confirm "DISPOSAL". Ref. to MECHANICAL (H4DOTC)>Cylinder Head>DISPOSAL .

Visually check the valve shim for damage.
Check the clearance between valve and valve shim. Check the clearance between valve and valve shim by measuring the outer diameter of valve stem end and the inner diameter of valve shim respectively.

Measure the outer diameter of valve stem end with a micrometer. If it is not within the standard, replace the valve.
NOTE:
- Measurement should be performed at a temperature of 20°C (68°F).
- Measure the outer diameter of the valve stem end at the two locations as shown in the figure, and read the value of most worn location.
- When the valve is replaced, lap the valve. Refer to "VALVE SEAT" for lapping. Ref. to MECHANICAL (H4DOTC)>Cylinder Head>INSPECTION>VALVE SEAT .
Valve stem end outer diameter:

Intake

Standard

5.455-5.470 mm (0.2148-0.2154 in)

Exhaust

Standard

5.445-5.460 mm (0.2144-0.2150 in)

Fig 1: Measuring Outer Diameter Of Valve Stem End With Micrometer
Courtesy of SUBARU OF AMERICA, INC.
Using a caliper gauge, measure the inner diameter of valve shim. If it is not within the standard, replace the valve shim.
NOTE:
- Measurement should be performed at a temperature of 20°C (68°F).
- Measure the inner diameter of the valve shim at the two locations as shown in the figure, and read the value of most worn location.
- If the valve shim has to be replaced, check the cam clearance and replace with the suitable valve shim. Ref. to MECHANICAL (H4DOTC)>Cam Clearance>INSPECTION>WHEN TIMING CHAIN ASSEMBLY IS REMOVED .
Valve shim inner diameter:

Standard

5.500-5.560 mm (0.2165-0.2189 in)

Fig 2: Measuring Inner Diameter Of Valve Shim
Courtesy of SUBARU OF AMERICA, INC.
Calculate the clearance between valve and valve shim. If the clearance exceeds the standard, replace the valve or valve shim, whichever shows the greater amount of wear or damage.

NOTE:

When the valve is replaced, lap the valve. Refer to "VALVE SEAT" for lapping. Ref. to MECHANICAL (H4DOTC)>Cylinder Head>INSPECTION>VALVE SEAT .
If the valve shim has to be replaced, check the cam clearance and replace with the suitable valve shim. Ref. to MECHANICAL (H4DOTC)>Cam Clearance>INSPECTION>WHEN TIMING CHAIN ASSEMBLY IS REMOVED .

Clearance between valve and valve shim:

Intake

Standard

0.030-0.105 mm (0.0012-0.0041 in)

Exhaust

Standard

0.040-0.115 mm (0.0016-0.0045 in)