Autolite 5143 gap on an N/A motor

[Stangfanatic06]

I'm going to use these as my new plugs with the screamin' demon I will be buying, since they seem to be doing well for yall here on the collective. I've searched but haven't found a solid answer as to what the gap should be for an N/A motor. I know the FI guys are running around .045, and the dealers claim .060 so what would you suggest?

[kena]

.065 .

[shb5007]

Not trying to take over here...but maybe someone can help me so I don't have to make another post.

What about the gap with these same plugs and the PH turbo kit?

[mrjimmy]

I know from first hand experience that with the screamin deamon coil,the most gap I can efficiently run with my Xcharger is 35. Otherwise it runs for s- - -.

You will find the bigger gap leads ti midfires and generaly poor performance...I had been as high as 50 and it ran piss poor

[dansv6rumbler]

I trust NicePony:

Originally Posted by Nice Pony

The gap is the distance measured in thousands of an inch between the ground or side electrode and the center electrode of the spark plug.

For most accurate gapping always use a round wire gapping tool.

Only remove the spark plugs when the engine is stone cold!!!!

Use antiseize compound on the threads of the new spark plugs and screw them in by hand until they bottom out then torque them to 13 lb-ft.

I'm not sure what gap people are running with nitrous but I would assume it would be similar to boosted applications.

Stock gap is 0.052-0.056.

With boost most of us run 0.035.

Or with boost and a screamin' demon coil 0.045.

If your are afraid of stripping #5 or any of them as far as that goes you can spray a little penetrant like Liquid Wrench Super Penetrant on the old plug as you remove it. Crack it loose just a little, spray on some penetrant then screwing it in and out just a little at a time until it feels like it will come out easy.

Also when you remove the spark plug wires make sure not to pull directly on the wires or you will damage them internally. Pull only on the boot around the wire with a twisting motion straight off and they will pop right off. They can be a little tight so watch what your doing or you can cut a finger or smash an elbow against surrounding parts.

I gapped my autolite 5143s to .052 about two weeks ago. Motor ran strong, even felt like I had more midrange power for some odd reason.

The plugs I replaced looked like originals (or possibly replaced) OEM motorcraft plugs... I changed them at 47K.

[Stangfanatic06]

Yeah, I read gaylon's post a while back but it only gives stock, boosted, and boosted+coil gaps. If you say you're running great with 0.052" on the low end of the stock gap, I'll try for the high end and go for 0.056" since the coil should be stronger and is "rated" for 0.060".

[JimC]

Boss (Chris) ran NA with the Screaming Demon so PM him and I'm sure he can remember what he gapped the plugs. As I recall he tried a couple of different ones and checked the plugs out to see how they were doing.

[Nice Pony]

Originally Posted by dansv6rumbler

I trust NicePony:



I gapped my autolite 5143s to .052 about two weeks ago. Motor ran strong, even felt like I had more midrange power for some odd reason.

The plugs I replaced looked like originals (or possibly replaced) OEM motorcraft plugs... I changed them at 47K.

I had to revise that since that post. With boost .045 works well with brand new plugs but quickly deteriorates. I am now running .040 with the Screamin' Demon which seems to stay running as strong as new even after many thousands miles.

Here are a couple of links I posted to since the referenced information:

http://www.mustangcollective.com/showthread.php?t=24718

http://www.mustangcollective.com/showthread.php?t=25628