Method of making a catalytic converter for use in an internal combustion engine

A method of manufacturing a catalytic converter for purifying exhaust gases from an internal combustion engine, the converter having a monolithic ceramic substrate surrounded by a supporting mat, comprising the steps of:

• wrapping a non-round monolithic ceramic substrate, having a major and a minor orthogonal axis and a peripheral surface, in a sufficient amount of the supporting mat material to substantially cover the substrate peripheral surface
• inserting the wrapped substrate into a metal shell having an external surface and a plurality of nodal points, the metal shell substantially surrounding the wrapped substrate;
• placing the metal shell in a resizing die exhibiting a pair of axes and having a plurality of adjacent fingers and associated gaps therebetween, the adjacent fingers extending axially along substantially the entire external surface of the metal shell whereby the nodal points of the metal shell are positioned along a portion of a die finger and the placement of the metal shell and wrapped substrate within the resizing die results in the axes of the resizing die being angularly offset from the major and minor orthogonal axes of the wrapped substrate;
• compressively closing the metal shell around the wrapped substrate by displacing the fingers of the resizing die radially inward to provide a gas tight seal and to impart a desired mat compression;
• and
• securing the metal shell to provide a gas tight seal and to hold the desired mat compression.