paulg_22

My truck is a 2003 Fx4 with 240,000 miles. Every so often lately I have an ignition coil fail and I just replace it. A couple of days ago cylinder 6 went and the truck also developed a large vacuum system leak. I limped home for about 10 miles.

So I was replacing the ignition coil first. I pulled the old one and found that it had disintegrated as you can see in the photo. While I was attempting to dig out chunks of rubber from the spark plug hole, I noticed that the spark plug was moving around. It wasn't even screwed in. I pulled it out and found that there was no gap. The side electrode had been pushed right down onto the central electrode.

Who knows how long I have been driving around with it like that. The amazing thing is that it was running fine until two days ago. I bought the truck about 4 years ago. I can't imagine how all that could have happened.

RLXXI

5.4L engine?

Hope you still have threads to screw a new plug into.

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paulg_22

Yeah, me too. It's a 5.4L

paulg_22

It appears to be stripped. Can't get the new plug to start. Looks like I'll have to go out and get a plug thread repair kit.

RLXXI

Good luck with that, back when this anomaly first appeared the only fix was to replace the entire head.

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Z7What

You can repair them. Get a time-sert, NOT a helicoil!

http://www.timesert.com/html/triton_repair.html

Wayne

RLXXI

Technology advancements always amaze me. I figured someone would have figured out a way to correct that MAJOR built in flaw from Ford, when it 1st reared it's ugly head there wasn't much that could be done because there was only 3 threads for the plug to seat with. Couple that with the fact the threads were aluminum = WTF were they thinking in the engineering dept.

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Z7What

The time-serts have helped a lot of people from replacing the heads. A lot of lightings guys that buy ported and polished heads have these installed in all the holes as a precaution. I'd love to know what cause them to shoot out. Has to be improper torquing of then. I had 100K on my 03 that 35K was pushing 12# of boost with no issues, have done tons of work on many other Lightnings and had a issue with the plugs shooting out after me changing them. My brother had a 99 Lightning with 225K and had no issues with blowing plugs either.

IIRC, the problem with helicoils is the material it's made out of causes a hot spot where it meets the head. If detonation happens it is normally at that hot spot and after time just eats away at the plug hole again and the plug blows again then the head needa to be replaced. Another small amount of info, out of all the places that sell heads for the 4.6/5.4 only one company(Trickflow) has it's own design head. All the others only port and polish and upgrade the OEM heads.

Wayne

RLXXI

From the factory the threads for the spark plugs were only 3 on the specific engine. Cylinder 4 mainly.



Yes I said 3 threads, why it only affected the rear most cylinders is something only an engineer can answer but it's an obvious fail and has since been rectified.

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Z7What

#4 & #8 are you hottest cylinders, they don't get the coolant flow to then as the others. That may have something to do with it.

In late late 03 and most of 04 they finally redesigned the head to 8 threads.

Wayne