Stripped exhaust manifold threads
 

So upon removing my oem manifold for the first time, the majority of the threads in one hole in the head came out with the manifold stud, that came out with the nut. So, I assume helicoil-ing it is the appropriate route? Is this something I should attempt to do on my own having never done this before, or take to a machine shop? Definitely have the appropriate tools to do it, only the guy knowledgeable enough that would typically give me a hand is currently house ridden to do surgery.

Suggestions?

Can't imagine why you couldn't do it. If machine shop, would you pull the head?

I recommend either a time-sert or a king sert. A helicoil is kind of a cheapo way to fix this, and much less of a permanent solution. Easy to install without removing the head.depending on which hole you stripped. ..

Agreed on the king-serts. Helicoil is a cheapo way out; may not stay in place. You want the ones with a positive locking mechanism to stay put.

If you're not comfortable to do it yourself, at least pull the head and take it in. Having the car towed in to do it in place is just one more variable to eliminate.

So you mean these?

Keensert

Yeah, I had the name KING in my head. Maybe it was a brand I used. Maybe my memory sucks. Either way, those are what you want. McMaster Carr could have them to you in one day.

Good deal. Will look into the Keenserts. Thanks! My only concern, and maybe it's just over thinking things, but could this be done with a hand drill (as opposed to a drill press)? Will the bit follow the original hole enough that it remains perpendicular to the flange?

I wouldn't worry about it. Maybe have someone spot you, just to make sure that your not holding the drill at some jacked up angle. It's amazing how you can be certain that you are drilling straight, and a dude walks up and tells you that you are crooked as hell.

About to do this. You have like an hour to tell me to stop. Keen serts purchased, and require an M14 hole. I'm scurred.

wait wut?

youre saying a stud came out with the nut, but also took threads out with it?

Were those the thin ones?

yes. It is a smooth hole in the head now.

Yes, the thin ones.

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Well finish it up, so we can see!

There were... complications.

More info when I fix it.

Awwwww crap. Sorry man. I hope it doesn't involve water or oil.

Nah nothing that bad. Threads didn't cut deep enough, I need bottoming tap. Trying to get the thing back out is a bit of a bitch. Trying something though. I think it'll work.

Wish I had noticed that, as you did post a pic of the tap. I think I tend to rush through the posts. A much better problem than a breakthrough. Take your time.

So here's what happened...

I drilled the 12.5mm hole, and tapped it m14x1.5. The problem was, when i threaded the insert in and tightened it down (using a bolt), it didn't go in far enough. And the bolt backed out without the insert. So, it was stuck.

So what we did was used red locktite put a bolt in, and let it sit overnight. Bolt came out perfectly the next day.

Since i didn't really feel like paying $40 for the only bottoming tap I could find locally, we used an angle grinder and rounded just the slightest bit of the insert. Worked great. MUCH better than a helicoil. Highly recommend it.

I paid: $6 for the insert (x2 for the one i broke with locktite), $7 for the tap, and $7 for the drill bit.

Pictures:

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Great! Those inserts are awesome aren't they?

On a side note, I have used and burned up every angle grinder on the market, the orange 4-1/2" harbor freight one is the best. The on sale $14.00 price tag is also a plus.

hey, great job!

Nice fix, I have used a heli coil in a pinch on a exhaust stud bolt hole it has stayed put for at least 30,000 or so miles. Whenever I have the head off I,m going to use one of those to fix to right.

Where did you source these? I cant find them anywhere.

If you could post the part numbers I would really appreciate it!
Vince

My local machine shop installed some for me. They don't even specialize in imports and had no problems coming up with them.

I just bought the Time-Sert master 1000 kit from Amazon. Got it covered!

This is the #1 thread on Google for fixing stripped exhaust studs for Miatas, so I figured I'd add my info here rather than starting a new thread:

I couldn't find Keen-serts for anything even approaching reasonable prices, and TimeSerts require the special tool to cut the shoulder the insert needs which also was super expensive (the kit someone mentions is like $400+).

I tried a helicoil repair kit, but for some reason I had a really tough time getting the coil insert to thread properly, which meant I wasn't able to get the stud to install properly back into the head.

I needed a new solution, so:
I was able to find a 10 pack of E-Z Lok inserts on ebay for $15 shipped (located under title: E-Z LOK 650-10F Thread Insert, M10x1.25, 33/64L, Pk10). These install with a large flat-head screwdriver, so no special tools required.
I got a stubby 31/64" drill bit for $15 on amazon (easier to drill with the engine in the car), and this set of tapered/plug/bottoming taps for $27: (Irwin Tools 2648-3)
You'll need a bottoming tap to avoid the issue Schuyler had.

I re-drilled the head, tapped with each successive tap, and was able to easily install the insert:

https://cimg3.ibsrv.net/gimg/www.mia...6d3786646c.jpg


Hope this helps anyone else who comes across this thread. The previous posters had a lot of info on the methodology, but no specific part numbers or costs, so hopefully this will give some guidance.

Thanks to everyone here who posted info. Just had to do one of mine with an EZ Lok and it was EZ!

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