06 Explorer 4.6 3V,need tap specs for spark plug

[JohnnyEx]

Rear left spark plug (Autolite HT1) broke off in manifold. Plug broke directly below the nut-between the nut and the threads. All the core material came out; extracted smaller diameter metal cone (that covers electrode) using autozone extraction tool, but larger diameter metal section with the threads (see attachment) remained in manifold. I'm not using any repair kits, I'm drilling and tapping(among other things). After a week of work with painstaking detail, I'm ready to tap. Autolite.com says the thread size is 16mm X 1.50. A tap&die distributors' website lists additional characteristics including thread limit (ex: D3), and thread standard (ex: metric or metric fine). I called both local Ford dealers near me in Orlando, who redirected me to Ford, who redirected me back to the dealer. Spoke to someone at Autolite, said he was a tech for 17 years&was unaware of the additional specs. Does anyone know the appropriate tap specs? I've been down w/out transpo for a week. I've ordered a tap from a local fastener disributor that will be here tomorrow. Not 100% sure it has all the right specs. Any input would be most appreciated.

 

[07EddyB]

Ouch. Did the Autozone extraction tool look like this?

https://www.amazon.com/gp/product/B00267PZUK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

If not, you might look into getting this specialized tool for these plugs. I'm not sure if its se tup for that part of the plug though.

And also, I believe the plugs are in the head - not the manifold. If yours aren't then no wonder you're having trouble!

 

[Bill MacLeod]

Didn't PL have a similar problem years ago and had some sort of workaround like what Johnny is proposing?

Hopefully he will see this thread and chime in.

 

[JohnnyEx]

Ouch. Did the Autozone extraction tool look like this?

https://www.amazon.com/gp/product/B00267PZUK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

If not, you might look into getting this specialized tool for these plugs. I'm not sure if its se tup for that part of the plug though.

And also, I believe the plugs are in the head - not the manifold. If yours aren't then no wonder you're having trouble!

Ouch. Did the Autozone extraction tool look like this?

https://www.amazon.com/gp/product/B00267PZUK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

If not, you might look into getting this specialized tool for these plugs. I'm not sure if its se tup for that part of the plug though.

And also, I believe the plugs are in the head - not the manifold. If yours aren't then no wonder you're having trouble!

Thanks for the reply. My terminology about where the plug lives may be wrong. And no that's not what the autozone extractor looks like, its what one of the Napa ones looks like, but I don't need an extractor now, I need (proper specs for) a tap

 

[JohnnyEx]

Just came across two pieces of info: 1) threads were described as "course" which rules out fine threads as an option, 2) autozone offers a different, more expensive kit (part #24200, $260 vs $130) which extracts and taps. Would have been nice to have known about the second kit a week ago...

 

[07EddyB]

As I understand it, the threaded portion is still in the head. So you plan to drill a big enough hole to remove it and the existing threads and then tap it?

I'm a bit confused on your plan because you are focused on the current thread size. You can't retap to the same size once you drill everything out. You will have to go to a thread repair to use the same spec spark plug again.
I'm missing something here I'm sure but I don't really understand your plan.

 

[07EddyB]

FYI - I looked at the 24200 kit you mentioned and that is not for your 2006. It is for the 96 to 03 engines that liked to spit plugs out. It's for when the plugs won't stay in - not for when they won't come out in one piece.

 

[JohnnyEx]

I plugged my vehicle info into autozone.com to check if that 24200 would work for my vehicle and it came back "ok". Oh well, too late to use that anyway. And about the broken plug hole, I haven't drilled out the whole thing. That would defeat the purpose. I've predrilled in preparation for the 16mm tap

 

[Explorer_PL]

Yep, exact my problem.
I used Dorman Help 42025 that is used for 2 valve Tritons, and it worked like a charm.

Dorman Products - 42025

https://www.explorerforum.com/forum...-other-cases-–-long-post.314791/#post-2735449

 

[shucker1]

You can't retap to the same size once you drill everything out. You will have to go to a thread repair to use the same spec spark plug again.

In all actuality it could be done if the head were off the engine. You would need something like a Bridgeport Mill and a really good selection of drill bits.

You would just keep shelling whats left of the spark plug threads up in size till you can grab a tip and pull out whats left like a big slinky..

With the head still on the engine you would be dropping too many chips in the cylinder for me...

 

[dacaur2]

You cant drill and tap a hole to the same size as it was. All you can do is extract the rest of the plug, then if you wish, you can use a tap to chase the existing threads and get out any rust/crap.
If you try to simply drill and tap it as if it were virgin metal, you will cause more problems than you solve. If you happen to start the threads exactly where they are now, you will be fine, but on the much more likley chance that you start the threads in a different spot, you will have two sets of threads in one hole, which basicaly means you will have really weak threads that will easily pull out....

The tap you will need to chase the threads is M14 x 1.25.

Your other option is to drill it out and use a helicoil. The helicoil kit will come with the right size tap and either include the drill or specify the drill size.

 

[Explorer_PL]

The insert I used does not require tapping, just drilling a hole of the right size, and then driving it down.
If you go that route, I would test the size of the hole using some flat piece of aluminium. Also, I recall I had to cut the 3 channels at the bottom of the self tapping insert.
Otherwise, you can have it fixed in an hour.
I just cut the boot and the spring on the coil since the plug sits higher.

PS: I just noticed I did that in April of 2011, whole life ago

 

[JohnnyEx]

Thank you everyone for your input. I'm not a mechanic but have always done my own work on my vehicles. Replaced the motor twice in my 89 Astro cargo van (RIP) 15 yrs ago, rear axle on the Astro and also on a 98 Grand Cherokee, and many smaller (lol) repairs.
It's been one of my worst weeks in memory, trying to keep the desperation in check, your input is truly very much appreciated.

 

[Explorer_PL]

Then you can do it. You are almost there. You have the old plug out, the hole is clean, check the size of that insert and drive that Dorman down there and fire it up.
In the end it just needs gas fumes, spark and compression, simple as that.
Don't overthink it.

 

[Bill MacLeod]

This site is filled with do-it-youselfers. We try to help each other if at all possible. Hopefully you get this resolved at minimal expense and get to enjoy your ride. Have a couple cold ones when you get a chance.

And ALWAYS use anti seize on the plugs.

 

[JohnnyEx]

The insert I used does not require tapping, just drilling a hole of the right size, and then driving it down.
If you go that route, I would test the size of the hole using some flat piece of aluminium. Also, I recall I had to cut the 3 channels at the bottom of the self tapping insert.
Otherwise, you can have it

The insert I used does not require tapping, just drilling a hole of the right size, and then driving it down.
If you go that route, I would test the size of the hole using some flat piece of aluminium. Also, I recall I had to cut the 3 channels at the bottom of the self tapping insert.
Otherwise, you can have it fixed in an hour.
I just cut the boot and the spring on the coil since the plug sits higher.

PS: I just noticed I did that in April of 2011, whole life ago

I just spent 45 mins on a detailed reply with pics and out of nowhere half of it magically disappeared. Using the links provided I read your original post and looked up that Dorman tool. My #8 plug hole was filled up with water which came from the cowl clips and wiring harness pins that penetrate the body panel going across above the firewall, adjacent to the hood gasket closest to the windshield. Water leaks through those down into the engine compartment.

There was a youtube video accomanying the Dorman tool. In the video, it says to remove the old plug which obviously I cannot do. I've drilled out with a 12" x 1/2" bit and then a 6" x 9/16" bit. Could not go deep enough with the 9/16" and so what appears to be the bottom section of the larger diameter metal section (the threaded section of the old plug) is what remains. In my desperation, but carefully nonetheless, I went ahead and re-tapped the hole with the 16mm x 1.5 tap. Btw, this was before reading your reply and watching the Dorman video. I was able to tap the hole but the plug will not drop all the way in. I think I know why and will work on that next.

But back to the Dorman tool, after watching the video, I remembered that the yellow coil for that plug was different from the black coils from the other 7 plugs(pictured). Appears as though the previous owner may have already done this type if repair, I'm not sure. Also in the Dorman video, I don't remember them drilling anything out. I may end up using the Dornan tool yet, but am concerned about the fact that it may already been done to this plug. Also concerned about using the Dorman tool when I have not yet been able to remove that very bottom larger diameter metal cone shaped section of the old plug.

 

[JohnnyEx]

Another btw: pictured is what I'm using to catch shavings. It's the originally-extracted metal cone section that covered the electrode. Using a grinder, I carefully cut off the flared upper lip of the cone, and very slightly filed the outer metal surface so it would slide down in the hole without being to loose. The red plastic piece pictured - there is one of those inside the cone. I then took a piece of ceiling grid pushed wire through the red plastic cup thing and shaped into the letter S. Makes for easy retrieval using another piece of wire with a very small hook on the end. Removed the fuel pump relay and bumped the ignition to get the piston high in the cylinder so I wouldn't have to fish it out a second time(1st time took approx 4 hrs)

 

[JohnnyEx]

Current pic of plug hole

 

[JohnnyEx]

And a small piece of plasic tubing taped into the hard hose section of my shop vac has done wonders pulling out anything that manages to make it past my defenses and into the cylinder. Read that tip on this forum - thanks again

 

[Explorer_PL]

Ok Johnny -

Not sure why I thought that you already drilled out the thread part of the old sparkplug below the hex. But it looks like you still have it there ?
I used an angle drill and we just drilled that part. I think I also used a vacuum cleaner with a 1/2 inch hose taped to the end, but cranking the engine with the starter blew out the shavings that fell into the cylinder.

Maybe you just need a longer 9/16 bit, and drop the piston down so you don't drill in it
If you decide to drive that Dorman insert there, do it gently so you do not shear it same way the plug did.
Like I said, it does not have to be perfect.
Watch this video in case you did not see it.

If the previous owner used that, you would know since the insert would be there.