2. Selecting a Heat Range<\/strong>
\n“It is believed by many that the heat range measures spark temperature or intensity. This is incorrect as the heat range is actually a measurement of the plug\u2019s ability to transfer heat away from the tip of the spark plug. One cannot change the temperature of how hot a fuel burns.<\/p>\nA hot spark plug has an insulator design that will be slower to draw heat away from the plug tip (thinner insulator mass), whereas a cold plug has an insulator design that will be faster to draw heat away from the plug tip (thicker insulator mass). For a spark plug to function properly it must have a tip temperature hot enough to invoke self-cleaning, while remaining cool enough to avoid pre-ignition.<\/p>\n
For most vehicles, the factory recommended heat range is sufficient; however, on some modified or special-use engines, alternative heat ranges may be necessary.”<\/p>\n
3. Torque<\/strong>
\n“Torque is critical in the plug\u2019s ability to dissipate heat and perform properly. The spark plug holes must always be cleaned prior to installation; otherwise, you may be torquing against dirt or debris and the spark plug may actually end up under-torqued, even though your torque wrench says otherwise. Of course, you should only install spark plugs in a cool engine, because metal expands when it’s hot and installation may prove difficult.”\n<\/ul>\n<\/p>\n