Ferd 4.6 2V blown sparkplug

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gzig5

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My son's 2001 Mustang GT Bullit just spit out the sparkplug from the #7 cylinder. Only 73,000 miles on the car. Apparently this is a common problem with the 4.6 and 5.4 two valve motors. Ford's recommendation is to replace the head but there are kits out there to install a bushing to restore the threads and it can be done without removing the head. The threaded inserts seems to be a popular solution but I haven't seen a lot of feedback on the longevity of it. Does anyone have any experience with this on-car solution? I would get the good quality kit from CalVan which is $220 if it will result in a decent fix. I simply don't have time to tear down the top of the engine at this time and install a rebuilt head or repair it myself. There are plenty of videos on the process and the biggest obstacle is getting all the chips out of the cylinder. I used a bore scope to look in and there appears to still be some thread left, it's not totally stripped, but I can't get the plug to start easily and I don't want to cross thread it. I'm going to try running in a thread chaser to hopefully get enough thread back to hold the plug tomorrow, but that is a stopgap measure. Even if the plug loosened and turned out instead of stripped the thread, there isn't much meat left and it needs to be addressed.

Amazon.com: CalVan Tools 38900 Two Valve Ford Triton Tool Kit - Foolproof Repair System, Spark Plug Thread Repair Kit. Tools and Equipment : Automotive

Buy CalVan Tools 38900 Two Valve Ford Triton Tool Kit - Foolproof Repair System, Spark Plug Thread Repair Kit. Tools and Equipment: Spark Plug Thread Repair Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
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Whomever designed that head with only three full threads to engage the sparkplug, should be hung from his nut sack. How could anyone with half a brain think that was a reliable design?
 
gzig5 said:
My son's 2001 Mustang GT Bullit just spit out the sparkplug from the #7 cylinder. Only 73,000 miles on the car. Apparently this is a common problem with the 4.6 and 5.4 two valve motors. Ford's recommendation is to replace the head but there are kits out there to install a bushing to restore the threads and it can be done without removing the head. The threaded inserts seems to be a popular solution but I haven't seen a lot of feedback on the longevity of it. Does anyone have any experience with this on-car solution? I would get the good quality kit from CalVan which is $220 if it will result in a decent fix. I simply don't have time to tear down the top of the engine at this time and install a rebuilt head or repair it myself. There are plenty of videos on the process and the biggest obstacle is getting all the chips out of the cylinder. I used a bore scope to look in and there appears to still be some thread left, it's not totally stripped, but I can't get the plug to start easily and I don't want to cross thread it. I'm going to try running in a thread chaser to hopefully get enough thread back to hold the plug tomorrow, but that is a stopgap measure. Even if the plug loosened and turned out instead of stripped the thread, there isn't much meat left and it needs to be addressed.

Amazon.com: CalVan Tools 38900 Two Valve Ford Triton Tool Kit - Foolproof Repair System, Spark Plug Thread Repair Kit. Tools and Equipment : Automotive

Buy CalVan Tools 38900 Two Valve Ford Triton Tool Kit - Foolproof Repair System, Spark Plug Thread Repair Kit. Tools and Equipment: Spark Plug Thread Repair Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com

Whomever designed that head with only three full threads to engage the sparkplug, should be hung from his nut sack. How could anyone with half a brain think that was a reliable design?
Click to expand...
Ford was to worried about their bottom line. I've heard that the 5.0 coyote is expensive to have rebuilt.
 
I would just install a interference fit Spark plug and send it


1749673746412.jpeg
 
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That was a very common problem with those early 60s aluminum headed Buicks. I remember having to do that repair bushing install on my Grandmother's Buick.
 
It requires a special tool to get the remainder of the plug out, be sure to put never seize on the threads of the new plugs. You will thank yourself later by doing this.
 
I recall yes the insert works you could also slather your brill bit or tap with grease and alot of the metal chips will stick to it etc. aluminum is non magenetic so you cant fish the metal chips out with a magnet maybe compressed air etc.
 

When I bought the GMC I decided "no Fords" and NO V engines, that is no V 4, 6, or 8 that were OVER HEAD CAM
 
Thanks for the feedback. I feel better about doing the insert now. I have been doing a similar repair on BMW aluminum oil pans for fifteen years with a bushing that I turn in the lathe myself, but all the work is done with the pan out of the car and very precise alignment in the milling machine. Should know by the end of the weekend where it stands. He's graduating tomorrow so there is already too much on my plate to get it done fast.
Just need to get this one hole sealed back up so the car can be used. Normally I'd change all the plugs at this time but the one that blew out is still gapped good and looks OK so I'm going to avoid the opportunity to strip another one on removal. When he's away at college this fall, I'll have plenty of time to pull the heads and do them all at once. I'll just have to resist the urge to port them and put in bigger cams while they are off....
 
gzig5 said:
Thanks for the feedback. I feel better about doing the insert now. I have been doing a similar repair on BMW aluminum oil pans for fifteen years with a bushing that I turn in the lathe myself, but all the work is done with the pan out of the car and very precise alignment in the milling machine. Should know by the end of the weekend where it stands. He's graduating tomorrow so there is already too much on my plate to get it done fast.
Just need to get this one hole sealed back up so the car can be used and when he's away at college this fall, I'll have plenty of time to pull the heads and do them all at once. I'll just have to resist the urge to port them and put in bigger cams while they are off....
Click to expand...
One of my Ford Tech customers did one in 20 minutes one day. It was one of the passenger front holes and out in the open. He charged a couple hundred dollars per hole and $50 for the insert. Way cheaper than pulling the head for replacement. It was a big money maker for him.
 
toolmanmike said:
One of my Ford Tech customers did one in 20 minutes one day. It was one of the passenger front holes and out in the open. He charged a couple hundred dollars per hole and $50 for the insert. Way cheaper than pulling the head for replacement. It was a big money maker for him.
Click to expand...
I think I'm going to have to pull the driver side fuel rail to get unrestricted access for the tooling. It's third hole back on driver side, so #7 in Ford's f'ed up world. Besides that, shouldn't take much more than half an hour, being meticulous to get all the chips out. I ran a M14x1.25 thread chaser in to try and save the thread. It went in pretty easy but threaded all the way in to the stop. But I can't get the plug to grab what's left of the thread, which isn't surprising. The bushing kit comes tonight via Amazon and I may have it ready by end of the weekend once the glue/epoxy dries.

Any thoughts on using both Loctite and JB Weld as was done in the video? Other video I saw just used high temp thread locker. I don't hate the idea but I know JB Weld starts getting soft around 300-350 degrees. Looks like there is plenty of thread engagement on the bushing to seal with threadlocker alone? I've got a new bottle of Loctite 272 which is supposed to be good to 450 degrees, but another video used 266 which . Not sure what there is a significant difference other than 266 being thicker?
 
67Dart273 said:
Do not use epoxy on those, the heat will fail it
Click to expand...
Kinda my feeling too. A good coating of the Loctite on the threads first and then the bushing should guarantee a gas-tight seal. As usual, I'm overthinking the problem, but I hate taking shortcuts and having to redo something.
 
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