Tech Info - Spark Plugs Overview

[85_Ciera_Rebuild]

Tech Info - Spark Plugs Overview (http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=US)

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Spark Plugs: Fact and Fiction (http://www.carcraft.com/techarticles/spark_plugs_tips/index.html)


Gasoline quality: With musclecar-era leaded gas, the lead is attracted to the hotter (core-nose) part of the plug, causing glazing. The spark runs down the core nose instead of jumping the gap. Going to a slightly colder plug helps prevent lead-glazing. However, with today’s cleaner-burning oxygenated unleaded gas, an equivalent engine needs to run plugs about 1-2 heat ranges hotter than originally specified (many plug manufacturers have revised their catalogs accordingly).

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Pictures of Spark Plugs (http://www.4secondsflat.com/plug_chart.html)

Note - This site deals with those using carburetion. Items 21 thru 24 would not be unusual for a fuel injected vehicle....seeing the white color....see first post in this thread, on their page 3 or 4...it shows a clean burning spark plug.

As a Corvette site noted

Many Corvette enthusiasts (http://www.corvettefever.com/techarticles/153_0503w_spark_plug_basics/power.html)make the switch from a conventional ignition system to a high-powered system of some sort, then claim the spark plugs are reading lean. Think about this: The air/fuel mixture hasn't been changed; how can the ignition system affect the air/fuel mixture? It can't, but because of the better burning properties of a modern ignition setup, changes may be required in the air/fuel mixture.

He is not talking about a vehicle using an O2 sensor to control fuel, but via carburetor.

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As noted in NGK's Tech Info here (http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp3.asp?nav=31000&country=US), "The borderline between the fouling and optimum operating regions (500&def;C) is called the spark plug self-cleaning temperature."

This is a key point for understanding your spark plugs in modern fuel injected motors. As shown in their picture there, if your plugs look similiar to the one shown, it means the right plug has been selected. When the spark plug is obtaining the self-cleaning temperature, it means a good combustion process is happening.

But, driving short distances without loading the motor, and driving long highway distances with higher horsepower requirements may require a different heat range for the plug.

One has to check their plugs visually to determine if a higher or lower heat range is required; the key secert here is how you will be loading (horsepower) your motor. On a air-cooled motorcycle, it was prudent to change the plug's heat range when changing from short hops to long distance runs, especially when driving in warmer weather conditions.

Hence, if the spark plug is running in the Self-Cleaning temperature, that's all that is important. Further, the above snippet in previous post above indicated that with "cleaner-burning oxygenated unleaded gas," the OEM's spark plug specs (for older vehicles) may have to be bumped up one or two heat ranges, for those burning "cleaner-burning oxygenated unleaded gas" (E10, for instance is "cleaner-burning oxygenated unleaded gas").