Just trying to narrow down exactly what is supposed to be. I see lots of posts about having the gap under .030 if tuned and if stock to be running .030-.032.

My confusion is both the SP534 and the superseded number to now SP580 both come with a factory gap of .035. I even looked at the owners manual and the manual even states .030-.033 gap for spark plugs but how does that make sense when the plugs they say to use are not gapped to that out of the box? I get that they usually want you to verify and make sure the gap out of the box matches what they are supposed to be but I have never seen the oem manufacturer to recommend a plug and a specification that don't match each other and in turn want you to change factory applied gaps to brand new spark plugs that match the box. Any clarification from you guys?

Thanks

 

If you're not tuned I'd gap them at .030

Tuned - .028

 

Gen 1 works best with .027" gap, especially with a tune. The Gen 2 will be good with .030" gap. Since the Gen 1 is Direct Injection only, like a Diesel engine, the smaller gap gives a better spark to help with ignition in the high pressure cylinders. The Gen 2 has DI and MPFI, the latter more conventional, and only runs DI under heavy loads, so the gap isn't as critical.

One other thing to note, the plugs use a very fine center electrode, and will eat a hole into the ground strap, which effectively increases the gap over time, which is why going to the .027" gap helps with a tune. When pulling a high mile plug from the EB, grab a magnifying glass and look, the crater is quite impressive.

 

I changed my plugs recently and used the Motorcraft SP534's. They came gapped at .031. These are what I pulled out, had a much wider gap due to wear. I was getting the misfire, stumbling and flashing CEL at 50k on the clock.

 

Mine is obviously a gen 1 and i do plan on tuning this truck so will it be fine to go ahead and set it at .027 for now until I am tuned?

Still seems weird to me that they recommend taking a brand new plug and closing the gap up. Whatever happened to specing a plug that is the correct gap to begin with?

 

I had 2 gen1's and ran a few sets of SP534, they came pre-gapped @ .030
I run SP550 in my gen2 and they come pre-gapped @ .028

 

I am not sure I have not gaped a plug to tolerance. I normally just tap them to close the gap or use the back of the gaping tool I have to open them. I never trusted them to be gaped correct out of the box. Is this a new thing? Not flaming you just never knew one to be gaped correctly.

 

No i get that, it just seemed weird that what they spec is actually different than what they say the spec is on the box of plugs you know. Having crappy quality control is one thing but actually specing them differently seems weird. Id say most just check one or 2, and if ok they just throw the set in and out the door. I guess im just overthinking it.

 

I would check them all. I am a firm believer that if I don't check one it will be the only bad one in the lot.

 

i hear that. They dropped em off at work. Just checked a few. Most were .030 and some .032. Ill just set em all to .030 and let it ride.

Weird though how everything online shows the part numbers as .035 plugs. Good job Ford. You’d think I would be used to this with International but I guess I had too much faith lol.

I dont know when I will be tuning forsure and if it comes down to it i will just throw a new set in again.

Appreciate it