Contents: Height clearance ↓ Gap in the lock ↓
Height clearance
1. Check the height clearance between the grooves and rings by inserting the ring into the corresponding groove (1 – piston ring, 2 – piston, 3 – feeler gauge set).
2. The nominal (calculated) clearance for the upper compression ring is 0.045–0.08 mm, for the second – 0.025–0.06 mm, and for the oil scraper ring – 0.02–0.055 mm. The maximum permissible clearances during wear are 0.15 mm.
Gap in the lock
3. Check the gap in the piston ring lock with a set of feeler gauges, inserting the rings into a gauge with a bore diameter equal to the nominal ring diameter with a tolerance of ±0.003 mm. For normal-sized rings, gauge A.96137 can be used.
4. The gap should be within 0.25–0.45 mm for all new rings. The maximum allowable gap when worn is 1 mm. If the gap is insufficient, file down the mating surfaces, and if it is too large, replace the rings.