Move the piston ring to the middle of the cylinder with the piston.
Pic. 2.155. Checking clearances in the piston ring lock: 1 – piston ring; 2 - piston; 3 - probe
Measure the ring gap in the lock with a set of feeler gauges (pic. 2.155).
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.