Installing Pistons

→ Wear personal protective gear.

→ Conscientious and precise work

Information 

• The pistons must already be pre-fitted (pistons, piston rings, connecting rods and fastening material) before performing the next step  .
• Note the association between the connecting-rod big end and the connecting rod bearing cap  .
• The retaining lugs of the connecting-rod bearing shells are always located on the same side in order to prevent the bearing shells from turning  .
  Fig 1: Identifying Connecting-Rod Bearings Retaining Lugs

  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
• The connecting rod bearing cap and the connecting-rod big end have cast lugs which must be aligned. These cast lugs lie on the same side as the twist lock (retaining lugs) of the connecting-rod bearing shells  .
• The cast lugs, twist lock (retaining lugs) and the flat side of the piston crown are on the same side  .
• Refit pistons according to removal markings (if being reused)  .
• If new connecting-rod bearing shells are used, there will be a red marking on the upper shell and a yellow marking on the lower shell  .

Information 

• Oil the bearing shells and bearing with engine oil  .

Information 

The cylinder head gaskets for the left and right cylinder head are shaped differently to ensure that they cannot be confused.

1. Install oil spray jets if necessary. → Tightening Torque: 9 Nm (6.5 ft. lb.) 
2. Move piston ring gaps by 120°.
3. Coat the cylinder liners, piston liners, bearings and piston ring restraining strap with engine oil.
4. Pre-fit upper bearing shell in the connecting-rod big end.

   The retaining lug on the bearing shell must fit into the corresponding cut-out on the connecting-rod big end.

5. Turn the gaps of the oil scraper ring so that the gaps are located at the oil piston shank area.

   The gaps of both rings and the springs must not be on top of one another (they should be offset slightly).

6. Universal Piston Ring Restraining Strap, 75 - 125 mm Nr. 55  must be positioned on the piston.

   Check that the piston rings are positioned correctly. Adjust restraining strap to the piston diameter, use tensioning lever -1-  and tensioning screw -2-  to fine-tune the adjustments.

   Fig 2: Positioning Piston Ring Restraining Strap

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
7. Insert piston, together with connecting rod, into cylinder bore 1.

   Universal Piston Ring Restraining Strap, 75-125 mm Nr. 55  must be positioned evenly on the cylinder surface.

   Fig 3: Inserting Piston In Cylinder Bore

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
8. Installation Position Of Piston 

   Installation position: Arrow -1-  on piston crown is pointing to the pulley.

   Fig 4: Identifying Piston Installation Position

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   NOTE: Incorrect handling of piston rings

   • Risk of strain and damage to piston rings

   → Only open up the piston ring using the piston ring pliers sufficiently to allow you to remove or fit it.

   → Do not use force to install pistons.

9. Hold the piston ring restraining strap firmly and press the piston into the cylinder bore using a plastic mandrel.
   Fig 5: Pressing Piston Into Cylinder Bore

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
10. Installation Position Of Connecting Rod 

    The larger collar on the connecting rods -arrows-  is facing the adjacent main bearing (shown on the front con-rod pair in the illustration).

    Fig 6: Locating Connecting Rod Installation Position

    Courtesy of PORSCHE CARS NORTH AMERICA, INC.
11. Place connecting rod bearing cap fitted with the correct bearing shell on the connecting-rod big end so that the retaining lugs of the bearing shells are on the same side.
12. Tighten New  connecting rod bearing screws hand-tight. Then tighten to the specified Tightening Torque. → Tightening Torque: 35 Nm (26 ft. lb.) → Torque angle: 90° 
13. Turn the crankshaft further so that the crank pin of the next piston to be installed is standing straight up.
14. Install the other pistons in the same way.