Just shot out a spark plug(2nd time)

[TekMan05]

Ironically I was about to start the Ex up to record a video so I could post it up here to diagnose I suspected vavle tapping noise. As I cranked it , it took a while then "*POP*. I immediately turned the key off and I noticed the 2nd from last plug on the driver's side shot out. This is the 2nd time for that exact one because last time I changed my plugs we didn't tighten down that plug hard enough and it did the same thing. It was still in the wire boot so we put that same plug back in and tightened it down. Now before this happened I was about to post a thread about a tapping sound I was noticing ever since I recently replaced both leaky TMH gaskets and still noticed a light tapping sound. The thing is this sound didn't increase with acceleration. Over the next couple of weeks it got progressively but slightly more noticable.
Another thing I noticed was a slight bit of heat coming from the driver's side but not the passenger's side. I even checked in the dark to see if it was a fried wire. Nope not sparking at all. Then today it spits out that exact same plug still intact in the wire boot. BTW I noticed also the day it got noticably louder that the Exhaust note had a very Very light pop pulse to the exhaust note. But it wasn't LOUD backfire pops. I even scanned the truck with the X-Cal device, no codes.
So I disconnected the battery for now and early next week I'm going to replace ALL Wires, Plugs, and I'm gonna put wire jackets around them this time as well. I just pray the thread in the head is not stripped! It may be time for an overhaul Just gotta thank the Lord this happened after I got my 2nd car!! TYJ!!

 

[eXcali]

wow, if it literally poped it out of the hole I would tell you to look at the threads of the hole and the plug both. If there is damage to the plug hole threads your in a VERY tight spot. The tapping sounds you hear was probably the plug being rattled loose.

If the thread on the head is stripped you can try to retap the thread just wide enuff to give it ridges then try to rebuild the thread with some sort of high heat jb weld or equivalent.

 

[ExploringNC]

Make sure you have the right plugs first of all. Is the spark end of the plug damaged at all? Is there metal in the threads of the plug?

I wouldn't retap it while still on the block. If the head is stripped, which it sounds like, you could helicoil it or have the hole filled in and retaped.

 

[Cobraguy]

They make thread repair kits for plugs. And your dealer should have the darn things in stock as often as Ford's spit plugs. I'm guessing this is a SOHC motor with aluminum heads? The mod motor boys have been fighting this for years. Even the 32V motors before Ford wised up and recast the heads with 7 threads instead of just 3. Here is what I can tell you has worked for me after spitting a plug on my wife's 5.4 Expedition and taking the head, coil, and a bunch of my wallet. First, use antiseize on the plugs. That will keep the plugs from galling and seizing in the head. But the problem is, the different metals between the plugs and heads and not enough threads to hold it. Heat expansion and contraction will loosen the plug over time. So every time I change the oil on any of my aluminum headed Fords, I retorque the spark plugs too. You would be amazed at how many times I've found one or two loose. Since I started that practice, I haven't lost a plug. (or head)

 

[Dan Whitaker]

They make thread repair kits for plugs. And your dealer should have the darn things in stock as often as Ford's spit plugs. I'm guessing this is a SOHC motor with aluminum heads? The mod motor boys have been fighting this for years. Even the 32V motors before Ford wised up and recast the heads with 7 threads instead of just 3. Here is what I can tell you has worked for me after spitting a plug on my wife's 5.4 Expedition and taking the head, coil, and a bunch of my wallet. First, use antiseize on the plugs. That will keep the plugs from galling and seizing in the head. But the problem is, the different metals between the plugs and heads and not enough threads to hold it. Heat expansion and contraction will loosen the plug over time. So every time I change the oil on any of my aluminum headed Fords, I retorque the spark plugs too. You would be amazed at how many times I've found one or two loose. Since I started that practice, I haven't lost a plug. (or head)

Cobra,

He has a 5.0

 

[gijoecam]

Cobra,

He has a 5.0

But there's no reason he couldn't use the same TimeSert BigSert system to do the job for his head as well. It would likely use a different insert, but I'm sure they make one that'll work.

-Joe

 

[410Fortune]

the only way a plug is popping out of a head after being installed and torqued is bad threads in the head

I was working on a 98 5.0L last night, pulling the #1 plug thinking about this thread... LOL

There is no way its just backing out on its own and going POP on a 5.0L your threads are damaged

BE THANKFUL this is on the drivers side, so much easier to work on over there......
sounds like plug #7

what a PITA!!

 

[gijoecam]

I, too, suspect there's something else going on... but if the threads were gone, how would it torque down? I'm also curious if he's torquing it by feel or if he's using a torque wrench set to the proper torque... it makes a difference, and when it comes to steel plug threads in aluminum heads, I always use a torque wrench.

Also, (not to hijack, but it bears mentioning) using anti-seize is not the solution (especially in the mod motors, and even more especially in 3-valve mod motors). If you torque it to spec using anti-seize or any other thread lubricant, you run a very real risk of stripping the threads. The lubricant allows the threads to slide more freely, thereby increasing the clamping force for any given torque when compared to dry threads. That clamping force must be resisted by the threads, and if the threads are gonna give, it'll be the softer aluminum ones that go first.

-Joe

 

[410Fortune]

geesh Ill stick with my cast iron heads... aluminum heads need spark plug clamps, not threads.....some other sort of hold down

3 threads? NICE ONE FORD!!

I have been in fear of the 4.6 and 5.4 for years now because of these horror stories

 

[TekMan05]

I think originally this happened the first time around because I didn't make sure it was properly tightened down. My fault for working in low light and being rushed in time to make it to work. I take it back I'm not gonna replace all the plugs right now, I'm not gonna throw the money away. I'll just have to buy that kit and hope all works well! And yess it's number 7 on the driver's side.

 

[Cobraguy]

You must use antiseize Joe or you will end up with a seized plug. Just about guaranteed. The problem is not torque values...the problem is a lack of threads cast in the head. That problem is being resolved with new castings.

Most all torque readings should be used with a lube. But it can be confusing as some lubes are better than others and can change the torque value. On spark plugs in aluminum heads and just three threads, it's wise to use common sense torque. And the with all the problems of removing plugs from three valves, well, that's another story. AFR also recommends antiseize on the plugs for their heads. In fact, any steel bolt going into aluminum should use it in my opinion.

By the way, I use it on the header bolts on my iron heads too. Had to pull a header the other day. All bolts were nice and tight...but once I broke them loose, every one turned out with my fingers. Now that is nice!