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Old 01-11-2010, 03:18 PM
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2door 2door is offline
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Join Date: Sep 2008
Location: Littleton, Colorado
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Default Re: Shorty Spark Plugs

Okay spark plug gurus...Take a look at these photos.
Look at the first one (left) and notice the difference in thread length between the NGK and the Autolite plugs. The Autolite is the crossover from a Champion plug, CJ7Y recommended by those who have used it. It also is a cross for the NGK BPM6A, the short version of the plug many of us use. At first glance you'd assume the longer threads would relate to a hotter plug. I saw the difference in thread length and told the counter man that it wasn't the same as the NGK. He layed them next to each other and told me to look at the reach of the electrodes. To my surprise they are the same. The porcelain is longer, more of it exposed below the threads of the Autolite shorty but the reach is the same as the NGK standard length plug, heat range determined by the length of the exposed electrode or the depth at the end of it? Obviously it is the total depth and thread length and porcelain placement has no bearing on heat range. Just curious.
Attached Images
File Type: jpg Plugs, 1.JPG (54.7 KB, 56 views)
File Type: jpg Plugs, 2.JPG (103.8 KB, 68 views)
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