Federal-mogul Corporation

Federal-mogul Ignition Company

Jeremy M Bowman

Kevin J Kowalski

Nathan A Thomson

A spark plug and a method of manufacturing the same, where the spark plug has a metal shell, an insulator, a center electrode, a ground electrode, and a gasket located over a threaded portion of the shell and used to seal the spark plug against a cylinder head. Once the gasket is attached on the spark plug, it is shrunk to become a post-formed gasket with an inner diameter that prevents the post-formed gasket from slipping over a threaded portion of the metallic shell. This process may be carried out with a collet type machine that produces a post-formed gasket that is flat and has a substantially uniform thickness, which can improve the sealability of the gasket. This may be important when the spark plug is installed in a cylinder head made from a lost foam casting process or other process that creates a somewhat porous sealing surface.

Spark plug gasket and method of attaching the same

A method of manufacturing a spark plug () for being threaded into a cylinder head () of an internal combustion engine is provided. The spark plug () includes a shell () with threads () disposed at a predetermined rotational position (a) relative to a shell outer surface () and ground electrode (). The position of the threads () relative to the ground electrode () places the ground electrode () in a desired position in the combustion chamber () and relative to components of the engine, thus allowing the ground electrode () to provide a robust and reliable ignition. When multiple spark plugs () are formed, the threads () in each of the shells () are repeatedly and accurately formed at the predetermined rotational position (&#x3b1;) by locating the ground electrode (), threads (), and dies () of a thread forming apparatus () in specific locations.

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Livonia, MI, United States of America

Jeremy M Bowman