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Old 02-23-2005, 12:06 AM   #1
poison
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Default What is the difference between gapping plugs @ .039 or .043?

All other things being equal, what difference does it make to gap plugs at the high end of the range as opposed to the low end? Or does it not matter?

Also, how do variances between the gaps on all four plugs affect things? Say 3 cylinders were .039 and one was .043. Does it negatively affect the engine?

Just trying to get an idea how anal I should be. Is close enough, or as close as I can, good?
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Old 02-23-2005, 12:48 PM   #2
Stealthbmbr
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I would get them as close to or close enough. Getting them exact would depend on the tool you use, and technique. I don't think it matters as long as it is with in the specified window of .039-.043.
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Old 02-23-2005, 05:15 PM   #3
Hayes
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I check the gap on all new plugs with a wire gage. If I find one outside thr 0.039-0.043 I set the gape to 0.040 inch and be done with it. Anything within the range is good. ed
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Old 02-23-2005, 10:19 PM   #4
deuce.five
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approx. .003"
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Old 02-24-2005, 10:10 AM   #5
poison
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Geez, thanks!

Seriously, does the longer or shorter spark make a difference in any way?
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Old 02-24-2005, 06:34 PM   #6
Legacy777
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The longer the distance the spark is, the more exposure it has to the a/f mixture. If you have a weak ignition system, or gap them too large, the spark will be weak, and could be blown out...mainly in forced induction applications. However if you have an aftermarket ignition that boosts ignition output, and you have the higher end gap, and more powerful spark it would be better in my eyes over a smaller gap.

However, we're talking about very small differences. If you're within spec, it shouldn't matter, and I doubt you'll see any difference.
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