Spark Plug Tools: Important

As some of you may know from another thread of mine I recently replaced my plugs. I have always been skeptic as to the accuracy of coins but here are some photos. I use to use the coins but most recently I used the wire gauge and to my astonishment for the first time ever all plugs were in spec per the reading on the wire gauge. The gap to me appeared to be to small with the coin. With the gaps set with the wire gauge it also seemed as if my truck was peppier and more powerful but maybe that was my imagination. These photos are with one of the old plugs I pulled out of my truck. I'm not sure which measurement tool is most accurate but this at least shows you the differences.

 

I just got out my 99 cent Oreilly's coin gauge and put a micrometer to it.

I gap at .40, so I measured there. It mic'ed exactly correct. I suppose there may be some variation caused by the sloping design of a coin tool, but I think it would be minimal.

 

On the K16TR11s for the 5VZ (1st gen V6), you actually need one of these L-shaped gauges because of the shape of the dual ground electrodes; they have tiny "devil horns" that prevent you from sliding in either of the other types of tools for an accurate read.

 

Hell, when I picked up six Densos from the dealer, I visually checked them at the counter. Two plugs has such badly aligned electrodes (grounds off center) that I rejected them and asked for two others. But all six I ended up with were dead on. So right there is a 33% chance they'll be screwed out of the box...