Assembling Pistons

Information 

• If re-using a piston, do not remove combustion residues on the piston crown mechanically. 

1. Clean the piston.

   Information 

   • Compression rings and oil scraper rings are installed and removed differently. 
2. Fit oil scraper ring.

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   Fitting oil scraper ring

   1. 2.1  Insert spring -1-  into the groove on the piston so that the gaps are touching.

      The gaps must not overlap.

   2. 2.2  Carefully spread the upper and lower discs using piston ring pliers -2 and 3-  and push onto the piston.
3. Allocate compression rings -1 and 2-  .

   Compression ring -1-  with chamfer -arrow A-  at the inner top side.

   Compression ring -2-  with shoulder -arrow B-  at the outer bottom side.

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   Allocation of piston rings

   CAUTION: Engine damage due to improper handling of piston rings! 

   • Engine damage and strain, damage to piston rings 
     1. → Do not overstretch piston rings with the piston ring pliers. Only open up the piston rings until they just fit over the piston.
     2. → Do not use force to install pistons.
4. Fit compression rings -3-  .

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   Compression rings

   1. 4.1  Grip upper compression ring -3-  at the gap using piston ring pliers.
   2. 4.2  Insert compression ring -3-  into the relevant groove -2-  on the piston -1-  .
   3. 4.3  Repeat the procedure for the lower compression ring -3-  .

   Make sure the gaps of the compression rings and the oil scraper ring are installed at an offset of 120° to one another.

5. Check the position and seating of the piston rings

   Information 

   The piston-pin circlip must be inserted fully in the ring groove of the piston.

6. Fit piston-pin circlip -1-  on one side.

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   Piston-pin circlip

   1. 6.1  Insert new piston-pin circlip -1-  into the ring groove of the piston so that the ring gap -3-  is offset with respect to the piston crown (6 or 11 o'clock position).

      Press ring gap -3-  into the ring groove with your thumb.

   2. 6.2  Carefully lever the piston-pin circlip -1-  into the ring groove using a small screwdriver while continuing to press it down.
   3. 6.3  If the piston-pin circlip -1-  cannot be levered correctly into the ring groove, lever the other end -3-  into the ring groove first.
   4. 6.4  Check that the piston-pin circlip is seated correctly -1-  .
7. Fit connecting rod -2-  .

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   Piston pin

   1. 7.1  Insert connecting rod -2-  into the piston -1-  and check that it is positioned correctly.
   2. 7.2  Coat the circumference of the piston pin -Arrow-  with engine oil.
   3. 7.3  Fit piston pin -Arrow-  and drive it in carefully using > VW222A - drift  .

   Information 

   The piston-pin circlip must be inserted fully in the ring groove of the piston.

8. Fit second piston-pin circlip -1-  .

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   Piston-pin circlip

   1. 8.1  Insert new piston-pin circlip -1-  into the ring groove of the piston so that the ring gap -3-  is offset with respect to the piston crown (6 or 11 o'clock position).

      Press one end -3-  into the ring groove with your thumb.

   2. 8.2  Carefully lever the piston-pin circlip -1-  into the ring groove using a small screwdriver while continuing to press it down.
   3. 8.3  If the piston-pin circlip -1-  cannot be levered correctly into the ring groove, lever the other end -3-  into the ring groove first.
   4. 8.4  Check that the piston-pin circlip is seated correctly -1-  .
9. Check piston and connecting rod for smooth operation.