Plug temperature question

[Steve]

B6ES-- north pole-- too hot for most of us.
B7ES hot-- winter time
B8ES cooler general use
B9ES colder-- hi performance or summer time riding
B10ES super cold -- death valley desert racing ultra high performance engine lots of timing advance

Just please remember:
The 'temperature' of the plug does not control the temperature of the combustion. Putting in a 'hotter' plug does not make the engine run hotter.

The 'temperature' of the plug is a measure of its ability to dissipate heat from combustion. A 'hotter' plug has a longer heat sink path, so it stays warmer. Hopefully, warmer enough to keep it clean. A 'colder' plug has a rather short heat sink path, so it tends to run cooler. This is desireable when you are running the engine hard, like in racing conditions.

When all is said and done, the actual temperature at the tip of the plug should remain in a range that is warm enough to keep deposits from forming, but cool enough to not light the mixture before the spark happens. And, this temperature will be about the same from one heat range of plug to the next, if they are used as intended. That is, the tip temperature of the B7ES that you put in for your low-speed commute should be about the same as the tip temperature of the B9ES that you put in for racing on the weekend.

But, rather than use hotter plugs to burn off deposits, why not fix what is putting the deposits there in the first place, and run standard plugs?


(No, I did not stay in a Holiday Inn Express last night. I actually attended a seminar several years ago that was put on by Champion Plugs. VERY informative.)

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