Installing Pistons

Information 

• Connecting rod bolts and bearing shells must always be replaced. 
• The marking on the main bearings and connecting rod bearings is located on the flywheel flange of the crankshaft. 

Information 

• The pistons must already be pre-fitted (pistons, piston rings, connecting rods and fastening material) before performing the next step. 
• Fit the number on the connecting rod -A- facing the exhaust side. 
• When installing the piston in the crankcase, the direction of travel arrow on the piston crown must point in the direction of travel. 
• The code on the connecting-rod big end and connecting rod cap must be on the same side -A-  .
  Fig 1: Identifying Cylinder Number Marking Surface

  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
• The direction of travel arrow is on the same side as the connecting rod code -A- on the piston shown. Fit the number on the connecting rod -A- facing the exhaust side. 
  Fig 2: Identifying Connecting Rod Code On Piston

  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
• The direction of travel arrow must be pointing forwards (in direction of travel) when installed -inset- . The combustion chamber recess -1- on the DFI piston is facing the inner V (centre of the engine) when installed -top arrow-  .
  Fig 3: Installing DFI Piston In Crankcase

  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
  Fig 4: Installing Piston

  Courtesy of PORSCHE CARS NORTH AMERICA, INC.

1. Turn the engine in the engine support so that the crankshaft lies at the bottom.
2. Install the piston. To do this, turn the crankshaft with a wrench (a/f 27) until the corresponding crank pin is pointing vertically downwards.
3. Lightly oil the cylinder, piston and funnel 9784/1  (-1-  ). Alternatively, a commercially available piston ring restraining strap piston ring restraining strap for 944 - S2 and Boxster and 911 Carrera (996) Nr.57  can be used.
   1. Oil the inside of the funnel
   2. Piston and connecting rod ready for installation
      Fig 5: Oiling Piston Funnel

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.
4. Align piston-ring set (staggered by 120°) and compress piston rings using piston ring restraining strap for 944 - S2 and Boxster and 911 Carrera (996) Nr.57  . Ensure that all piston rings are correctly tensioned by the special tool -siehe illustration-  . If you are using a funnel 9784/1  , slide the piston with connecting rod fitted into the funnel -2-  . The collar of the funnel must be facing the crankcase -1-  . Slide the piston into the funnel until the piston shank protrudes approx. one centimetre down out of the funnel.
   Fig 6: Inserting Piston Into Piston Funnel

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   Fig 7: Inserting Piston Into Piston Funnel

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   Fig 8: Inserting Piston With Strap

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
5. Place piston onto cylinder from above and push into cylinder. using the handle of a hammer if necessary. When doing so, make sure that the direction of travel arrow is pointing forwards -siehe arrow (Abbildung zeigt Zylinder 1)-  . If you are using the funnel 9784/1  , position it flush on the crankcase -3-  . Check the position of the combustion chamber recess -1-  and the direction of travel arrow when doing this.
   Fig 9: Installing Pistons

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   Fig 10: Fitting Piston

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
6. Push the piston downwards until the connecting rod bearing is sitting on the lift pin. Push it down further using the handle of a hammer if necessary -siehe illustration-  . Do not use force. If the piston is jammed in the tool, oil the tool again if necessary or carefully loosen and turn the piston.
   Fig 11: Pushing Piston Downwards

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
7. Oil connecting-rod bearing shells and crank pins.

   Information 

   • The piston connecting rods are cracked and only fit in one position (in conjunction with the matching numbers). 
   • Install con-rod code towards exhaust side -A-  .
     Fig 12: Identifying Cylinder Number Marking Surface

     Courtesy of PORSCHE CARS NORTH AMERICA, INC.
8. Then fit the connecting rod cap with bearing shell (twist lock together). Retaining lugs for connecting rod bearings -B and C-. The connecting rod numbers must be facing each other. View of matching numbers -A-. Fit connecting rod bolts by hand.
   Fig 13: Identifying Connecting Rod Bearing Retaining Lugs

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   Fig 14: Identifying Matching Numbers On Cylinder Surface

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
9. Fit the opposite piston (cylinders 1 and 4).
10. Fit other pistons using the procedure described above.
11. Turn crankcase on the assembly support until the crankshaft is on top.
12. Tighten connecting rod bolts that have been replaced. Turn the crankshaft until the corresponding crank pin is pointing vertically upwards. Tighten bolts with a multiple-tooth nut.
13. Once all pistons have been correctly fitted and secured, turn the crankshaft in a clockwise direction to check it using a ring wrench (a/f 27). When doing so, watch out for stiffness and irregularities. If the crankshaft cannot be turned or if it is very stiff, check whether the installation direction (arrow) of the pistons, the pistons and the cylinders (markings) and the connecting rod caps and connecting-rod big end all match.