The term hot/cold is commonly used to describe whether a spark plug heats up easily (hot) or whether it provides resistance to heating up (cold). Be the first to know about sales and promotions. Some NGK Racing Plugs are also available in half heat ranges. As the air temperature or humidity decreases, the air density increases, requiring a richer air-fuel mixture. Spark Plug, Racing, Tapered Seat, 14mm Thread, 25mm Reach, Heat Range 8, With Resistor, Each. They have a longer insulator tip and they achieve a temperature higher than … Therefore, it is impossible to chart an Autolite heat range hierarchy, let alone a standardized comparison to other spark plug brands. For NGK Racing Plugs, the heat range is located AFTER the hyphen. A colder heat range spark plug may be necessary if the ignition timing has been advanced to near the knock level. Heavy knock can cause breakage and/or erosion of combustion chamber components. When the spark plug firing end (tip) temperature exceeds 800°C, pre-ignition originating from the overheated insulator ceramic can occur. This basic guide is designed to assist the technician, hobbyist or race technician in understanding, using and troubleshooting spark plugs. Pre-ignition occurs when the air-fuel mixture is ignited by a hot object/area in the combustion chamber before the timed spark event occurs. The heat range of a spark plug is the range in which the plug works well thermally. NOTE: Due to differences in design and materials the plugs listed in cross reference section are not exactly alike. If the heat range is too cold, the spark plug will be unable to properly self-clean by burning off carbon deposits. Call us at 713-459-6977. NGK spark plugs use a heat range index ranging from 2 to 12 with 2 being the hottest spark plug and 12 being the coldest. However, sparks don’t just simply ignite. Therefore, the path for the dissipation of heat from the insulator nose to the cylinder head is longer and the firing end stays hotter. Sponsorship Opportunities New applications for the 2021 season are now being accepted from 8/1/2020 through 11/30/2020. The heat range must be carefully selected for proper spark plug thermal performance. Starting with part # BKR6E-11 (heat range 6), a colder plug would # BKR7E-11 (heat range 7), a hotter plug would be # BKR5E-11 (heat range 5). Thermal conductivity of the insulator, center electrode, etc. For example, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. As a result, spark plug tip temperature will also decrease. It takes a high amount of precision to create spark plugs that perform their task well and are extremely resistant in doing so. The heat rating is a measure of the amount of heat dissipation.The heat range of a spark plug is the range in which the plug works well thermally. View full size version of NGK performance plug numbering chart. As the air temperature or humidity increases, the air density decreases, requiring a leaner air-fuel mixture. To contact them, click here. (The number after the “-“ is the gap.). (Knock is sometimes referred to as “spark knock.”) Retarding the ignition timing will reduce knock. If it the heat range is too hot, your engine could experience detonation, pre-ignition, or power loss. The two most common causes of spark plug problems are carbon fouling (< 450°C) and overheating (> 800°C). We are not NGK Spark Plugs USA. Pre-ignition occurs when the air-fuel mixture is ignited by a hot object/area in the combustion chamber before the timed spark event occurs. If the selected spark plug heat range is too cold, the spark plug may begin to foul when the engine speed is low or when operating in cold conditions with rich air-fuel mixtures. 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