Identification Of Pistons

Information 

The piston is identified as a spare part by the following characteristics: one dimensional group X, Naturally aspirated  or Turbo  , cylinder bank 1 to 4  or 5 to 8  .

The piston is installed as standard in two additional weight tolerances: + and -. 

This information is all engraved on the piston crown. To identify the piston uniquely, the piston must be cleaned carefully (brass brush, ultrasound bath).

Markings on piston crown:  Replacement pistons are only available from the Porsche Parts Service in dimensional group 'X'  and in two weight tolerances '+' and '-'  .

Fig 1: Piston Classification

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

1. Inspection stamp (supplier)
2. Arrow marking in direction of travel
3. Porsche short numeric code without main or middle number
4. Cylinder bank identification
5. Marking area for weight group (weight tolerance)
6. Marking area for dimension group
7. Barcode 128 (short numeric code (without main group) and weight group)
8. Direction of travel arrow
9. Short numeric code (supplier)

1. In the event of repairs, the removed piston must be cleaned and identified. If the piston needs to be replaced, an X  piston with the identified weight tolerance + or -  for the correct cylinder bank is ordered and installed as a spare part.