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Old 11-27-2014, 04:13 PM   #1
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Default Spark plug thread repair.

Since I almost have everything ready to get the turbo in, I had to do the dreaded task of fixing the plug threads on cyl#3...

The last time I pulled the plugs to check for a rich condition when I was working on crank tuning when I installed MS, I noticed that cyl#3 only threaded in a few turns before getting tight. I could see down the hole and could tell a majority of the threads were missing... The car has 153k on it and who knows how long it's been this way, but I knew it had to get fixed before I added boost.

My Dad's a tech, and has been for 30+ years, and has used this to fix the Ford Triton plug blowouts:

thread insert


spark plug thread chaser

I had to grind down a few threads to make the insert flush with the end of the plug. They also have 1/2" inserts that should work as well.

I did the procedure today and it took maybe 45 minutes. Loaded up the chaser with grease and ran it down the hole. Stopping every 5 or so threads to check how deep I was. It bored out the old remaining threads and tapped in the new ones very easily. I cleaned up the mess, started it without the plug to get any other debris out, then boogered somed red lock tite on the insert and sent it down the hole with the plug in it. After seating it all the way, I backed out the plug and the insert stayed put and that was that. Seems like a solid repair and he hasn't had any failures using them on the Fords.

Just wanted to share!

Happy Thanksgiving,

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Old 11-27-2014, 11:26 PM   #2
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Nice job, it sounds like.
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