Piston: Application and ID
Piston wear, weight groups and identification markings
Information
Weight groups and identification markings
Information
Original pistons from Porsche are only available in the dimensional group X.
Observe the different weight groups.
Piston markings
Identification markings:
1 - Manufacturer's logo
2 - Date of production
3 - Manufacturer's drawing number
4 - Weight group
5 - Arrow marking for intake side (visible on new pistons)
6 - Data matrix code
7 - Porsche part number
8 - Dimensional group
Checking
Checking for wear
Warning
Caustic fluid
Danger of chemical burns
- Avoid contact with caustic fluid.
- Wear personal protective gear.
- Ensure that there is good ventilation.
- If you do come into contact, wash off immediately with plenty of warm water and contact a doctor if necessary.
Information
When cleaning pistons, be careful of the hard layer on the first ring groove.
Be careful of the twist lock for the second ring groove.
1. Clean removed pistons with solvent naphtha or acetone first. To determine the dimensional group (engraved on the piston crown), carbon deposits must be removed carefully.
1.1. To do this, we recommend that you clean the piston crown in an ultrasound bath or using a brass brush.
Information
If the wear limit is exceeded, the piston must be replaced.
2. Check the piston diameter -D- at the prescribed measuring point on the piston shank using an outside micrometer.
Measuring point from lower edge of shank dimension X = 15 mm.
Checking the piston shank diameter
The maximum wear allowed at the specified measuring point is 100 microns (= 0.1 mm). If this measurement is exceeded, the piston must be replaced. The reference measurements are listed in the table below.
Piston rings and piston ring groove:
Piston rings:
3. Check piston rings for signs of wear.
3.1. Piston-ring end clearance is measured in the cylinder.
Piston pin:
- Check for signs of wear and tear.
- Dimensional check using outside micrometer: diameter = 22.0 - 0.02 mm.