Move the piston ring to the middle of the cylinder with the piston.
Measure the ring gap in the lock with a set of feeler gauges.
Checking clearances in the piston ring lock:
1 - piston ring;
2 - piston;
3 - probe
Ring gaps:
- for the upper compression ring, the clearance should be within 0.15 - 0.30 mm for K4M 760 and 761 engines, for other engines - within 0.15 - 0.35 mm;
- the gap for the lower compression ring should be in the range of 0.4 - 0.6 mm;
- the gap for the oil scraper ring should be in the range of 0.2-0.9 mm.
Replace piston rings if gaps are out of tolerance, and if gaps remain out of tolerance with new rings, replace cylinder block.