Installing Valves

→ Remove all valve grinding paste fully after grinding.

Information 

• The valves cannot be touched up afterwards  .
• The valves can be ground using commercially available valve grinding paste  .

1. Apply a small a fit of valve grinding paste to the valve seat.
2. Oil the valve stem of a new valve and insert it into the valve guide from the combustion chamber. Push the valve in until it is seated securely in the valve seat of the cylinder head.
3. Grind down the valve with a commercially available valve grinder (with a rubber suction cup) using rotating movements. To do this, grip the valve grinder between the palms of your hands and press it against the valve seat in rotating movements → Grinding the valve seat  .
   Fig 1: Grinding Valve Seat

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4. Carry out the grinding operation for each valve that is replaced. Check for leaks using some fuel and installed spark plugs. The fuel must not escape through the valve seat. Carefully remove valve grinding paste.
5. Fit valve lock → Locking valves 
   Fig 2: Identifying Valve Lock

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6. Replace valve stem seals. For details, see → 156355 REPLACING VALVE STEM SEALS 
7. Fit valve springs, concave washer and valve keys. To do this, place valve springs (there are two in the exhaust valve in the turbo engine) on the bottom concave washer. Place top concave washer in position.

   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.

8. Insert the valve keys into the assembly cartridge.
   1. 8.1. Press the spring-tensioned washer of the assembly fixture down -1-  and insert the valve keys -2-  with the narrow end down.
      Fig 3: Pressing Valve Key In Assembly Fixture

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   2. 8.2. Ensure that the valve keys fit symmetrically and are inserted as far as they will go in the tool. The spring-tensioned washer automatically locks the valve keys in place.
   3. 8.3. Position the assembly cartridge -2-  so that it is centered on the assembly fixture. Observe installation position of the valve keys -1-  .
      Fig 4: Identifying Assembly Cartridge

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   4. 8.4. Press the assembly cartridge against the spring force onto the assembly fixture. The knurled screw moves forward. Turn the knurled screw back and forward until the valve keys engage. Repeat this several times if necessary. → Assembly cartridge grips the valve keys Fig 5
      Fig 5: Assembling Cartridge Grips Valve Keys

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   5. 8.5. Check that the valve keys are held symmetrically in the assembly cartridge -1-  .
      Fig 6: Identifying Valve Keys

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9. Place the valve key assembly cartridge onto the cylinder head (same as removal of valve) and position it on the top spring plate.
10. Press the assembly cartridge down against the valve spring force using a lever (assembly fork) and keep it pressed. The knurled screw moves forward. Turn the knurled screw back and forward until the valve keys engage → Installing valve keysFig 7. Repeat this several times if necessary.
    Fig 7: Installing Valve Keys

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11. When installing the valve keys, check that they are positioned correctly.