SAE J1998_199804

Defines the essential dimensional features of R, B and M rectangular piston ring types, with narrow ring width. Dimensional Tables 8 and 9 allow for use of cast iron and steel. As the modulus of elasticity of steel rings is greater than for cast iron, the fluctuation in the surface pressure will be greater should the free gap be set as the reference for force. Forces are therefore set using the surface pressure as the reference, so as to minimize the effect of the fluctuation. Applicable to rectangular rings for reciprocating internal combustion engines not in excess of 90 mm diameter for cast iron rings and not exceeding 100 mm diameter for steel. Also suitable for use for piston rings of compressors working under similar conditions.

Differences, where they exist, are shown in Appendix A.This SAE Standard specifies the essential dimensional features of R, B, and M rectangular piston ring types with narrow ring width.Dimensional Tables 8 and 9 allow for the use of cast iron (Table 8) or steel (Table 9). Since the modulus of elasticity of steel rings is higher than that of cast iron rings, the fluctuation in the surface pressure will become greater if the free gap is set as the reference for force. Therefore, forces are set using the surface pressure as the reference, in order to minimize the effect of the fluctuation.The requirements of this document apply to rectangular rings for reciprocating internal combustion engines up to and including 90 mm diameter for cast iron rings and up to and including 100 mm diameter for steel. They may also be used for piston rings of compressors working under similar conditions.