Spark plug for internal combustion engines

An assembly for a spark plug deeply arranged in a spark plug recess provided in an intrnal combustion engine, the spark plug comprising a mounting portion, a center electrode means, and an insulating body, comprising

• extension means adapted to be attached to the spark plug for facilitating access thereto, the extension means includes a center electrode, an insulating means, and a tubular jacket with at a first end an inner cross-sectional configuration corresponding to a cross section of the mounting portion of the spark plug, and at a second end a mounting means,
• means for enabling an attachment of the insulating body and center electrode of the extension means to the spark plug,
• means for retaining the tubular jacket at the insulating means of the extension means,
• means for sealing the first end of the tubular jacket with respect to an insulating body of the spark plug,
• means for sealing the second end of the tubular jacket with respect to the insulating body of the extension means, and
• means for sealing the tubular body with respect to the spark plug recess.