This standard covers complete general and dimensional specifications for most commonly used metric thread high pressure fuel injection line fittings and the related components with which they are assembled.

The basic type of fuel injection tubing connection is the swaged-tapered seat type identified as Type 2 (to correspond to the similar design in SAE J521) and is specified in

Fig. 1 and Table 1

. This type is available in two designs, Style A and Style B, the latter having a collar and nut designed to provide support of the tubing beyond the end of the nut. These connections consist of an upset tapered male seat formed on the end of the high pressure tubing itself (

Fig. 1D ), which is compressed against the mating seat in the pump discharge or nozzle inlet fitting ( Fig. 1C ) by means of the collar ( Figs. 1E or 1G ) and the nut ( Figs. 1F or 1H ). (See assembled connections, Figs. 1A and 1B

.) Upsetting the seat on the end of tubing requires special tools and experienced personnel, and after swaging the inside diameter of the upset portion of tube must be reamed to its original size.

The following general specifications supplement the dimensional data contained in

Table 1 with respect to all unspecified detail.