Valve Guide Servicing

In order to avoid spreading the end of the valve guide when removing it, mill the guide down to the head on the camshaft side. A 0.433" (11 mm) drill bit may be used if milling tool not available. Drive valve guide out into combustion chamber.
Using a hole gauge, measure bore in cylinder head. Turn oversize guide down in a lathe so that O.D. gives an interference fit of 0.0024 - 0.0035" (0.060 - 0.090 mm).

Fig 1: Top View Showing Timing Chain Alignment
Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Fig 2: Cross Section of Valve Guide Installed in Head
Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Fig 3: View of Engine from Blower End (Rear of Car) Showing Valve Timing Marks
Courtesy of PORSCHE CARS NORTH AMERICA, INC.
Press valve guide into head from camshaft side until a measurement of 0.5196" (13.2 mm) is reached. See Fig 2. Use suitable grease as a lubricant when pressing in valve guides. Bore or ream valve guide I.D. to 0.3543 - 0.3549" (8.99 - 9.01 mm).