Checking Piston Wear
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2019 Porsche 911, 2018 Porsche 911, 2017 Porsche 911, 2016 Porsche 911, and 2015 Porsche 911. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
Caustic fluids
- 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.
- 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.
- 1.1. To do this, we recommend that you clean the piston crown in an ultrasound bath or using a brass brush.
- 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 .
The maximum wear allowed at the specified measuring point is 100 μm (= 0.1 mm). If this measurement is exceeded, the piston must be replaced. The reference measurements are listed in the table below.
Dimensional groups:
Dimensional group (in mm) MA1.03 engine MA1.04 engine Wear in mm I 101.964 - 101.976 96.964 - 96.976 max. 0.1 X 101.974 - 101.986 96.974 - 96.986 max. 0.1 II 101.984 - 101.996 96.984 - 96.996 max. 0.1 Piston rings and piston ring groove:
Piston rings:
- Check piston rings for signs of wear.
- 3.1. Piston-ring end clearance is measured in the cylinder.
Designation Ring end clearance in mm Explanation 1st piston ring < 0.4 mm Measurement in cylinder 2nd piston ring < 1.0 mm Measurement in cylinder, check gap ends (twist lock) 3rd piston ring < 0.8 mm Measurement in cylinder Piston rings:
Designation Dimension in mm Ring groove 1 1.2 + 0.15 Ring groove 2 1.5 + 0.15 Ring groove 3 2.0 + 0.15 Piston pins:
- Check for signs of wear and tear.
- MA1.03/MA1.04 engine: Dimensional check using outside micrometer: diameter = 22.0 - 0.02 mm.
- 3.1. Piston-ring end clearance is measured in the cylinder.