21/30434652 DC

This standard 21/30434652 DC BS ISO 6621-4. Internal combustion engines. Piston rings is classified in these ICS categories:

• 43.060.10 Engine block and internal components

This part of ISO 6621 specifies the general characteristics of piston rings for reciprocating internal combustion engines for road vehicles and other applications (the individual dimensional criteria for these rings are given in the relevant International Standards). It also provides a system for ring coding, designation, and marking. It is applicable to all such rings of a nominal diameter from 30 mm up to and including 200 mm.