Removing Valve-Stem Seals

Information 

When required, all valve-stem seals on both cylinder rows must be replaced.

Information 

• Before switching to another cylinder, the cylinder must be positioned at the bottom dead centre and supplied with compressed air (see above). 

Information 

• Position the pistons of the relevant cylinder at the bottom dead centre. 
• Each piston is pressed downwards as pressure builds up in the cylinder. 

1. Position the pistons of the relevant cylinder at the bottom dead centre. To do this, guide the control chain carefully when turning the crankshaft.
2. Screw compressed air hose from tool set > VAS 5161A - removal and installation device for valve keys screw in additional > VAS 5161A/33 - valve key assembly add-on kit or similar tool set into the relevant spark plug bore and tighten it. Ensure a constant compressed air supply to the cylinder (at least 6 bar overpressure). This builds up pressure in the cylinder so that the valve does not fall into the cylinder while you are working.  Replace all four valve-stem seals for a cylinder and refit valve keys. Only then fit compressed-air hose on the next cylinder and apply compressed air constantly.
3. Fit the tool on the cylinder head and adjust it.
   1. 3.1 Screw in holder -1-  with a suitable thread into the matching thread on the cylinder head. The hook piece -2-  is pre-fitted in the holder.

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Installing hook

   2. 3.2 Insert a suitable plastic guide -1-  instead of the tappet.

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Inserting plastic guide

   3. 3.3 Insert assembly cartridge -1-  for the valve keys into the plastic guide.

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Inserting assembly cartridge

   4. 3.4 Mount the lever (assembly fork) -1-  on the hook and place it correctly onto the assembly cartridge. Make sure that the tool and equipment can be used without tilting.

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

   Tool fitted correctly

4. Remove valve keys.
   1. 4.1 Press assembly cartridge with lever (assembly fork) down against the valve spring force and keep it pressed > Pressing tool down  . The knurled screw on the assembly cartridge is pushed forward -1-  .

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Pressing tool down

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Pressing down lever and knurled screw

      Information 

      The mechanic must practise for use of the assembly cartridge to be effective. Some repetitions must be made to ensure that the valve keys are correctly held in place.

   2. 4.2 Turn the knurled screw back and forth -1-  until the valve keys snap into place -2-  in the assembly cartridge and are held there. The knurled screw retracts.

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Turning knurled screw back and forth

   3. 4.3 Remove assembly cartridge and check correct position of both valve keys -1-  .

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.

      Valve keys in assembly cartridge

   4. 4.4 Pull knurled screw on the assembly -1-  cartridge and tap out the valve keys -2-  .

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

   Removing valve keys

5. Remove valve springs, concave washers and valve keys from the cylinder head.

   Information 

   For space reasons, pliers can also be used for removing the valve-stem seal. Example HAZET 791-5

6. Pull sliding sleeve from the > 3364 - Puller. When positioning the > 3364 - Puller on the fitted valve-stem seal, ensure that the metal edge of the valve-stem seal is positioned behind the corresponding metal edge of the puller. -1-  > Valve-stem seal in puller 

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

   Valve-stem seal in front of puller

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

   Valve-stem seal in puller

7. When engaging the > 3364 - Puller, push sliding sleeve down and close the tool -Arrow-  .

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

   Closed puller

8. Remove valve-stem seal by activating the negative (slide) hammer -Arrow-  . Repeat procedure for valves on pressurised cylinder (reposition tool accordingly).

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Removing valve-stem seal