2. Check the piston ring clearance by height (Figure 2.37). If the value is greater than the permissible value, replace the piston ring, piston, or both parts together.
Figure 2.37. Checking the piston ring clearance
Normal clearance:
- Upper compression ring - 0.03-0.06 mm.
- Lower compression ring - 0.02-0.06 mm.
- Acceptable value: 0.1 mm.
3. Install the piston ring into the cylinder bore.
4. Press the piston ring with the piston so that it is positioned at a right angle to the inner bore of the cylinder (Figure 2.38). Then measure the gap in the piston ring joint using a gauge.
Figure 2.38. Install the ring perpendicular to the cylinder
If the gap is greater than the permissible limit, replace the piston ring.
Normal value:
- Upper compression ring of 12-valve engines - 0.20-0.35 mm,
- Lower compression ring for 12-valve engines - 0.20-0.35 mm.
- Compressor rings for 8-valve engines G13B, 4G13, 4G15 - 0.20-0.40 mm.
- Oil scraper ring - 0.20-0.70 mm.
Valid value:
- Compression rings - 0.8 mm.
- Oil scraper ring -1.0 mm.