Porsche 911 GT3 R 2012, Техническое руководство

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3.8.4. Valve clearance
The valve clearance is measured between the cam follower and the cam
lobe heel when the engine is cold.
Inlet valve clearance [mm] 0.22 – 0.25
Exhaust valve clearance [mm] 0.22 – 0.25
3.8.5. Valve spring adjustment
The valve springs are set based on spring travel. The setting is the same
for inlet and exhaust valves.
The following procedure must be adhered to:
1. Compress the complete spring assembly (outer and inner spring
and upper and lower valve spring seats) till coil-bound with a
spring balance, before reducing the stack height slightly (0.7 –
1.0 mm)
2. Record the spring stack height (seat to upper edge of spring
seat)
3. Add the valve-lift to the measurement resulting from the
procedure described above. The resulting value is the fitted
spring stack height
4. Fit the valve and upper spring seat to the cylinder head, close the
valve by pulling the spring platform
5. Measure the distance between the upper edge of the spring seat
and the valve spring seat
6. Compensate for the difference between the calculated
measurement and fitted-spring-length with shims during assembly