Then please tell me why after I replaced them did the truck run fine?
Rock auto .com sells them for much less then what? $7.99
I am not sure about what you are saying.

 

I don't know the specifics of what was wrong with your truck. Maybe you did have them seated well, maybe you had a misfiring cylinder or two, maybe you got a bad plug, maybe it was a figment of your imagination ... the list can go on. My point was that the plugs work as well or better than any other, and we have the data to prove it.

When I bought the 515's a few months back, I got the set of 8 for a little less than $70. The 507's would have been $60 I believe. The price difference is neglible though, I was just mentioning that rock auto sells them at about the lowest price I've found.

 

I'll use the Champion plugs as insurance against problems till Motorcraft makes a solid design.

 

x2. Why replace the problem with the problem? 20k miles strong on the champions so far.

 

You aren't replacing it with a problem. The new plugs have a tapered shank and will come out without a problem. Of, course, my original set came out without a problem, too.

 

X2. New design on plug and my original set came out just fine @ 60K miles.

 

My only point was you said it was not the plugs, but you were not here and you had not used the plugs I had in my truck. You may have the same brand and model number, but not the ones I had. Please don't get me wrong I know you are just trying to help. But where I am confuse is why are the resistant so different. I am going on DATA not just I but in a set of plugs and they work so no other thing can vary from your scenario. If it worked for you then anything else is someone's imagination
I also agree with bluejay the new plugs are tapered and I think have a coating on them. The ones I pulled came out very easy. I would not worry about the new two part plug.

 

Neither the 507 or the 515 have any tapered shank, if anything they might be slightly smaller in diameter than the originals and have a tighter crimp. Both myself and the local Ford parts guy measured the shanks (w/micrometer) on about a dozen plugs...no difference and no taper on any of them.

 

That's odd. The service manager at my dealer(he is a member here and I trust him completely) told me that they are smaller, reduced in size, tapered or whatever, to allow them to come out when there is carbon buildup. He said this, assuring that they will be removed with no breakage. Are you sure you were comparing thenm to the very first original plugs?

 

I measured the old/new plugs with a vernier caliper as well, and found no difference between the two, but I didn't spend too much time on it. In any case the anti-seize should eliminate any problems new or old.

 

I did not say MY data, I said Ford had data. Do you really believe that if the motorcraft replacement plugs made the trucks run bad, that it would go unnoticed? Seriously, it would be an epidemic, and I hate to use off the cuff statistics, but I would bet that over 50% of the F150's (04-08 obviously) who have had the plugs changed went back in with Motorcrafts and have had no poor engine performance.

My point was that you didn't narrow down that the plugs you had were the culprit except by replacing them with a different brand. What happens if you exchanged the Motorcrafts you bought with a different set of Motorcrafts and it ended up running perfect?!! Again, there is a bit of error in left in your statement that Motorcrafts made your truck run poorly.

 

X2....correct....

 

We didn't have any of the old stock plugs to compare to and we were only looking for the taper and found none out of all of them. The only thing that he was aware of was that they were crimped much tighter at the manufacture (again unofficial). Couldn't tell if the shank was smaller or not. In thinking about this, not sure if a smaller or tapered shank would help anyway...it just gives carbon more room to accumulate and harden. That was just our unofficial assessment, Bluejay...in no way was I trying to be critical of you or anyone here on the forum .

 

Didn't take it as critisizim at all. We are just trying to get the facts out there, try to help each other. I too wondered if it would only allow more build up, but, I also believe that if you run a good gas with a good detergent, you are much more likely to have minimal build up. Thinking back to what Landon said, he probably was saying that the shank is slightly smaller that the OEM plugs. Regardless, that dealership is having little trouble getting the plugs out.

I talked to the service guy at the dealer in Athens, TX and they are having lots of trouble. I think it has a lot to do with how they go about it. They don't even want to do the job and start at $550 where the Burleson dealer starts at $350.

 

"Again, there is a bit of error in left in your statement that Motorcrafts made your truck run poorly" [/QUOTE]

I am not sure what your statement above means,
Maybe you meant that there was some room for error in my statement?
Again THE SET OF PLUGS I INSTALLED CAUSE MY TRUCK TO RUN BAD. Not that all Motorcraft plug will cause every truck to run bad. See the different?
Because the SP515 I installed in MY truck did cause the truck to run rough. No I did not want to install another set of SP515 from the same vendor. If a different vendor would have had the SP507 or SP515 in stock where I could have tried them that day I would have liked to tried that also. I wanted to get the truck running well again. I had just paid $18000.00 for it and was worried. SoonerTruck, I am not saying bad thing about 99.9% of Motorcrafts parts. I am just saying the plugs I had gave me problems. I would be glad to ship them to you and you can install them and see how they perform for you. I just wish I could get some good hypothesis of what may have happen and not people getting upset that I told that a motorcraft part may have caused me problems.

I think you need to reread my post. Below is what I said

"I am not saying anyone should use the HT1 I am just tell what happen to me today and hope it may help someone later"