Attention! In normal practice, the piston, piston ring and connecting rod are not disassembled. When replacing the piston, the piston pin, piston ring and connecting rod are replaced together as a single element.
Fig. 2.162. Measuring the piston diameter
Measure the outside diameter of each piston at a right angle of 90° to the piston pin 10.0 mm above the piston (fig. 2.162).
If the piston diameter is less than the standard, replace the piston, piston pin, piston ring and connecting rod assembly.
- Piston diameter L8: 82.965–82.995 mm;
- LF, L3, L3 (with variable valve timing mechanism): 87.465–87.495 mm.
Measure the clearance between the piston and the cylinder.
If the value is not within the standard, replace the piston, piston pin, piston ring and connecting rod assembly.
- Normal clearance: 0.025–0.045 mm.
- Maximum gap: 0.11 mm.
Fig. 2.163. Measuring the gap between the piston ring and the ring groove
Measure the gap between the piston ring and the ring groove around the entire circumference of the piston (fig. 2.163).
If the clearance exceeds the maximum, replace the piston, piston pin, piston ring and connecting rod assembly.
Normal clearance:
- upper: 0.03–0.08 mm;
- second: by 0.03–0.07 mm;
- oil scraper: 0.03–0.07 mm.
Maximum clearance:
- top: 0.17 mm;
- second, oil scraper: 0.15 mm.
Fig. 2.164. Measuring the piston ring gap
Insert the piston ring into the cylinder and, pressing the ring with the piston, move it to the bottom point. Measure the gap in the lock of each piston ring with a feeler gauge (fig. 2.164).
If the clearance exceeds the maximum, replace the piston, piston pin, piston ring and connecting rod assembly.
Standard clearance:
- upper: 0.16–0.31 mm;
- second: 0.33–0.48 mm;
- oil scraper: 0.20–0.70 mm;
- maximum gap: 1.0 mm.