Preliminary Work

With engine installed => 

1. Remove high-pressure pump on cylinder bank 5 to 8.

   > WM, 246319 REMOVING AND INSTALLING HIGH-PRESSURE PUMP

2. Detach the cable plug of the solenoid valve for valve lift switchover.
3. Remove vacuum pump on cylinder bank 1 to 4.

   > 477619 REMOVING AND INSTALLING VACUUM PUMP

4. Detach the cable plug of the solenoid valve for valve lift switchover.

   If cylinder head is replaced => 

5. Remove screw plug with sealing ring. -1- 

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Screw plug on secondary-air duct