Cam Clearance: Adjustment

Remove the engine from the vehicle. Refer to MECHANICAL(W/O STI)>ENGINE ASSEMBLY>REMOVAL .
Remove the chain cover. Refer to MECHANICAL(W/O STI)>CHAIN COVER>REMOVAL .

When adjusting #1 and #3 cylinders

Remove the timing chain RH. Refer to MECHANICAL(W/O STI)>TIMING CHAIN ASSEMBLY>REMOVAL>TIMING CHAIN RH .
Remove the cam carrier RH. Refer to MECHANICAL(W/O STI)>CAM CARRIER>REMOVAL>CAM CARRIER RH .

Measure the thickness of valve shim using micrometer.

NOTE: Measurement should be performed at a temperature of 20°C (68°F).

Courtesy of SUBARU OF AMERICA, INC.

Select a valve shim of suitable thickness using the measured cam clearance and valve shim thickness.

NOTE: Use a new valve shim.

Intake side: S = T + 1.69 x (V - 0.13 mm (0.0051 in))

Exhaust side: S = T + 1.87 x (V - 0.22 mm (0.0087 in))

S: Valve shim thickness required

V: Measured cam clearance

T: Current valve shim thickness

Install the cam carrier RH. Refer to MECHANICAL(W/O STI)>CAM CARRIER>INSTALLATION>CAM CARRIER RH .
Check all the cam clearance of RH side at this time. If the cam clearance is not within the standard value, repeat the procedure over again from step (2).
NOTE: When the removing/installing of cam carrier RH has been performed, cam clearance may be outside the standard value. Checking of all cam clearance of RH side is necessary. Refer to INSPECTION of "Cam Clearance" for the cam clearance inspection. Refer to MECHANICAL(W/O STI)>CAM CLEARANCE>INSPECTION>WHEN TIMING CHAIN ASSEMBLY IS REMOVED .

Cam clearance:

Intake

Standard

0.13^+0.02_-0.03 mm (0.0051^+0.0008_-0.0012 in)

Exhaust

Standard

0.22±0.02 mm (0.0087±0.0008 in)

When adjusting #2 and #4 cylinders

Remove the timing chain LH. Refer to MECHANICAL(W/O STI)>TIMING CHAIN ASSEMBLY>REMOVAL>TIMING CHAIN LH .
Remove the intake manifold. Refer to FUEL INJECTION (FUEL SYSTEMS) (W/O STI)>INTAKE MANIFOLD>REMOVAL .
Remove the cam carrier LH. Refer to MECHANICAL(W/O STI)>CAM CARRIER>REMOVAL>CAM CARRIER LH .