3.8.5. Check of gaps between piston flutes and rings


Fig. 3 — 28. Check of a gap between piston rings and flutes: 1 — a piston ring; 2 — the piston; 3 — a set of probes

Check a gap on height between flutes and rings as shown in fig. 3 — 28, inserting a ring into the corresponding flute.
The nominal (settlement) gap for the top compression ring makes 0,045–0,08 mm, for the second — 0,025–0,06 mm and for oil scraper — 0,02–0,055 mm. Maximum permissible gaps at wear — 0,15 mm.
Check a gap in the lock of piston rings a set of probes, inserting rings into the caliber having diameter of an opening equal to the nominal diameter of a ring with the admission 0+ _ 0,003 mm. It is possible to apply caliber of A.96137 to rings of the normal size.
The gap has to be within 0,25–0,45 mm for all new rings. A maximum permissible gap at wear — 1 mm. If a gap insufficient, you zapilit butt surfaces and if raised — replace rings.