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Discussion Starter · #1 ·
The manual says plug gap is .040
NGK website says the gap for their V-power plugs is .044

What is correct, what do you all use?

On my 1970 Dodge Dart Swinger I open the gap from the stock .035 to .040 and my car loves it. Would our 2.5L like the extra gap as NGK suggests?

Thanks,

Tim
 

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Most spark plugs are designed for multiple applications, and therefore they are not always gapped properly for your vehicle. With that in mind, it doesn't matter how they come out of the box, but what your car needs.

I have run my NGKs are .040 as recommended. That's not to say it won't work at .044, but a little experimentation may find a "better" setting for your car that may not apply to others.

As astrochimp said, it's not the size of the gap, but the intensity of the spark. If your ignition system cannot handle the extra gap, you'll get misfiring... if it can, then it may be working harder, or it may not matter.

I'll be sticking to .040 unless anyone can prove some other gap is really better.
 

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astrochimp said:
Ok, u totally Lost me..
how are you relating spark intensity with compression..


The thing I would add is What is the gap of the plugs out of the box that you bought for your car?
Who cares what the website says.
Compression during the compression stroke of the engine can "blow out" the spark. So, yes, it has something to do with spark intensity. Of course, if you are having that problem, then your spark is not intense enough. I didn't mention this before because it was beyond the scope of the question.

As for the gap of the plugs "out of the box", as I said before, the plugs are "generic" and designed for many applications. For this reason, they may need different gaps depending on the different electronic systems in each application. Hence, the 0.040 gap recommended by Mazda applies to our cars... so it's best to stick with it, unless you have evidence of a "better" gap.

The NGK ZFR5F-11 plug that is recommended for MX6 V6 engines is supposedly a very common plug (as shown here: http://www.philsinc.com/ngkpricing.html ). Obviously, this isn't because the only application is on the MX6 - it must be used elsewhere. One example is the webpage ( http://brutus.rightpathnetworks.com/site08/repairlog/sparkplugs.htm ) that mentions this plug is also used on the Dodge Viper V10 engine. This page ( http://www.surplusparts.com/INVENTORY - VW _ AUDI.html ) implies that the plug is used on other applications including VW Golf, Jetta, Passat, BMWs, etc. Heck even our sister car (the Probe) uses a slightly different plug.

So, as you can see, the variety of applications means there is a variety of electronic systems behind the plug (and various compressions) which means you may need a different gap from what's provided "out of the box."
 

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Discussion Starter · #7 ·
Wow SCHWINN you so smart!

You make me me want to go gap some plugs right now!

Wait, that didn't sound right.......

Honestly, I have never used a plug out of the box without checking and regapping first, exactly for the multiple application reason.

But I got the impression from the NGK website that they were suggesting the plug be used at .044 for the MX-6 application. Not that .044 was what it came pre-gapped as.

But i shall take your word for it. Besides this car is so sensitive to the slighest variance I don't want to start experimenting with it now.

Tim
 

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Spark Plug Gap is specified as 0.039 - 0.043 in the repair manual... Checking gaps should ALWAYS be done. For example, I changed my plugs last weekend, all plugs were gapped correctly, except 1 which was at like 0.046(too large)...Moral of the story: Plugs arent always gapped as the box states.
 
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