Patent ID: 7073471

Claim:
A spark plug adapter particularly for use in an internal combustion engine and allowing utilization of a high-performance spark plug to improve combustion, engine smoothness and fuel economy, as well as power output, the internal combustion engine having a spark plug port including a threaded section opening to a combustion chamber of the engine, the spark plug port including a step adjacent to and outwardly of the threaded section and providing a sealing surface, and the spark plug port being configured to receive a conventional spark plug which in sequence along its length provides: an electrode section providing a spark gap in the combustion chamber of the engine, a metallic portion with a threaded portion for threadably engaging the threaded section of the spark plug port and leading from the electrode section first to a sealing shoulder engageable with the sealing surface, and an external metallic body section which provides wrenching flats, and which carries an insulator section with a metallic electrical contact; said spark plug adapter comprising: a body portion externally replicating the configuration of said conventional spark plug including said threaded section, said sealing shoulder, and said external body section with wrenching flats; said body portion internally defining a stepped through bore providing a substantially straight non-threaded bore portion within said threaded section, and said through bore opening at one end of said body portion to a combustion chamber of said engine, said bore portion extending internally of said body to an outwardly disposed and tapering seat section; a radially outwardly extending recess above said tapering seat section, and including a non-threaded section extending to a threaded section of said stepped through bore, and said threaded section opening on said body portion; whereby, said spark plug adapter is configured to receive a high-performance spark plug which in sequence along its length provides: an electrode section providing a spark gap, and an adjacent elongate metallic non-threaded cylindrical section, which leads to a tapering sealing shoulder, which is defined adjacent to a metallic threaded section, and leads to an external metallic body section, the external metallic body section providing plural wrenching flats, and carrying an insulator section with a metallic electrical contact.