911 Carrera S Cabriolet (997) F6-3.8L (2007)
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.