Proper spark plug gap (update)

[FlipTrac_511]

I've read that the proper gap for the Motorcraft (SP-500) spark plugs is about .054 to .056. The closest measurements my gauge has are .050 and .060 so I went shopping for a new gauge that has .054 to .056, but I could not find any with these measurements. The only thing I can think of doing is bending the side-electrodes of my plugs so that the .050 wire on the gauge just fits nicely in the plug gap, while the .060 will not fit at all.



What have you folks used to get proper gaps and are there gauges available with .054 or .056 measurements? The difference may be negligible but if I'm gonna do the labor I might as well give the minor details attention.

 

[Dingo]

I think most of us just buy pregapped plugs.

 

[Scott Heckler]

The gap tool at the counter of the Autozone was the size of a half dollar and it has every range you would need. I had to gap mine larger due to the new coil.

 

[Eric H]

I simply use a feeler gauge to get the proper gap.

 

[FlipTrac_511]

A half dollar is .085". My Ford shop manual says spark plug AGSF22PP should be gapped .061-.068". This spec should be the same for the AGSF22FM (replaced the PP) right?

 

[Jeff C]

Flip,



The one Advance and Autozone sell is the size of a half dollar, but it has the gapper on the edge. It gets larger along the edge of the quarter, so all you do is slide your plug along til it won't fit, then read it off. Make it larger or smaller, and adjust til it's exactly right, no guessing.

 

[Tom Schindler]

If not, set it for .060" and then tap is slightly smaller.





Tom

 

[FlipTrac_511]

Cool, thanks for the info folks. I just got my replacement wires (and clip-on separators) today too so I'll be doing the plugs and wires very soon.

 

[FlipTrac_511]

I'll be doing my plugs and wires today and as I did a last minute review of things I discovered a discrepancy for the proper spark plug gap.



The project on this site and along with the sticker under my 04's hood indicates a gap range of 1.32 - 1.42mm (note that my sticker indicates the gap in metric, whereas the sticker shown in the project has it in inches). However, my Ford shop manual and Alldata.com mention the gap to be 1.57 - 1.73mm.



Which should I use???

 

[Gavin Allan]

Always use the underhood emmission sticker gap.

 

[FlipTrac_511]

I figured as much Gavin. I decided to do that and gap the new plugs at .054". Project done, will post another...