Oh No!

[Paul T. Casey]

Driving to work this a.m., I picked up a bad miss. It knocked a little, then went away. It seems okay at speed (2000rpm) but she's running pretty rough at idle. I'm hoping a plug or coil went bad. I'll let all know as I investigate further. :depress:

[01True BlueGT]

Do you have a K&N filter?

[Paul T. Casey]

Here's what I know so far. I opened the plug cover on the right side, and found a plug (second from front right bank, can't remember how they're numbered right now) popped out. This also has ruined this coil. The plug is pretty beat up, I'm hoping just from banging around in the sleeve. :eek:

[Paul T. Casey]

Spark plug hole is stripped. May need to bring it to the shop.

[Dr Caleb]

Spark plug hole is stripped. May need to bring it to the shop.

Oh My $Deity

You may need a new cylynder head.

[Paul T. Casey]

That's what the dealer said, worst case senario of course. I'm going to try to tap the first two threads myself first.

[junehhan]

That really sucks.........

Out of curiosity, how many threads in the head hold the plugs for the Marauder in place? If the threads are stripped, you may need new heads as suggested since it's generally advisable that you don't try to use anything to fix it like that heli-core stuff...........

[FordNut]

Paul,
I guess you're out of warranty (unluss you have the extended warranty) but just out of curiosity what plugs are you using? The OEM plugs on early builds did not have threads all the way to the end. There was a TSB to change to a revised plug which has threads all the way to the end. The Denso plugs do have threads all the way to the end. If the problem is related to the short threads, maybe you can approach your dealer about it and possibly get some help. If you have plugs with full-length threads, the problem was probably related to either over- or under- tightening the plugs when they were replaced.

Don't recall the TSB number, but it was posted on here somewhere.

[FordNut]

You sure that crash didn't cause this problem? Go back to the insurance company for repair of "hidden" damages!

[TAF]

You sure that crash didn't cause this problem? Go back to the insurance company for repair of "hidden" damages!
NOW you're thinkin Brian :up: ;)

[TripleTransAm]

I think I'd be nervous tapping any threads into a cylinder head due to the risk of metal particles ending up in the combustion chamber.

[Paul T. Casey]

Bad news, there's no thread left in the hole.
Good news, I have extended warrantee. I also have a lot of confidence in the local dealer here in Huntsville. Steve, I concur on the slivers thing, but I have found that if you coat your tap with Vaseline, not only do you get lubrication, but the gel seems to hold most of the shavings, a moot point however in my case. I'm hoping that the warrantee folks somehow err on the work order and I end up with a Lightening motor stuck in the Marauder. That would be cool. (Just a fantasy I dreamed up last night.) I also hope it's back together in time for FFW next week.

[mcb26]

Pearman L.M. has always done good work for me. I bought my first car from them a 1963 galaxie with a 427.

[Paul T. Casey]

Yes, Pearman is good! They did my body work, job was so weel done I brought them a "thank you" gift last week. Looks like that may have also been a good move! mcb26, I'll pm you later today, got to go do some work now.

[SergntMac]

What I'm wondering now, is the pathology for this breakdown. What's your take on the cause, Paul?

[BillyGman]

Until Paul answers that question, let me say that my guess is that someone had to have cross threaded that plug while installing it.

[FordNut]

Until Paul answers that question, let me say that my guess is that someone had to have cross threaded that plug while installing it.
Not necessarily so, Billy. The 5.4 is notorious for this problem. There are only a few threads making contact. Too loose or too tight and the threads are gone. That is part of the reason for the spark plug TSB where the threaded length was changed.

[Paul T. Casey]

Most plausible theory to me is tolerances/plug thread length. In the future, I'll probably add checking plug tightness to my personal PM (preventative maintainence) list. I already do a weekly "walkaround," check brake pads, rotors, lug tightness, fluids, battery holddowns, overall under hood inspection, and look around the underside. I think over 50K miles, I probably should have made sure the plugs didn't loosen. On my older cars, I would have taken them out for an inspection by now, but, I felt the newer plugs wouldn't wear, so I left them alone. If the holes/threads are slightly on the"large" side of tolerance, it's possible for plugs to loosen over time. Just my opinion, no scientific basis or facts to back it up.

[BillyGman]

Not necessarily so, Billy. The 5.4 is notorious for this problem. There are only a few threads making contact. Too loose or too tight and the threads are gone. That is part of the reason for the spark plug TSB where the threaded length was changed.

But does the 5.4L engine require a taper seat plug, or a standard/gasket seat plug? I'm thinking that if it's a taper seat plug then it might have some thing to do w/the threads getting stripped on the 5.4L engine. The plugs on the Marauder heads aren't the taper seat type and just stop dead when you're tightening them, so there isn't a whole lot of guess work as to exactly how tight to go w/them if you're not using a torque wrench whereas I think that w/some cylinder heads that call out for a taper seat plug, that isn't the case. And who uses a torque wrench for installing plugs? not anyone that I know.

[FordNut]

But does the 5.4L engine require a taper seat plug, or a standard/gasket seat plug?

I'm not sure, but I believe it is the same type plug we use. How about it, some of you Lightning owners?


And who uses a torque wrench for installing plugs? not anyone that I know.

I do, and if you don't use one with aluminum heads, you're asking for trouble.

[junehhan]

On the pre 03 models for the Lightning, I believe that the plugs are held down by only 4 threads in the head. The heads were later revised sometime during the 03 MY from what I understand. Out of curiosity, how many threads hold down the Marauder plugs?

[hitchhiker]

Pearman L.M. has always done good work for me. I bought my first car from them a 1963 galaxie with a 427.

Cool Car! :up:

Best Regards,

David

[BillyGman]

Well if the heads only hold the plugs by merely four threads, this might be cause for concern since they're aluminum heads. I'd be surprised if that's the case, but when it comes to new cars these days, stranger things have happened.

I never use a torque wrench on sparkplugs since the required torque on them is so light. It doesn't require muscle to get them in. You just make sure that you don't over do it. But I'm not talking about the installation of taper seat plugs either. Our Marauders don't require taper seated plugs.