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-   -   StripPed exhaust stud (https://www.miataturbo.net/diy-turbo-discussion-14/stripped-exhaust-stud-31265/)

patsmx5 02-07-2009 09:05 PM

StripPed exhaust stud
 
This sucks. While back I had the upper, most forward stud get loose. Like the actual stud backed out of the head, and when I tried to tighten it, the stud turned in, not the nut. Well, it tightened up then, but now it's leaking again and I tried to tighten it and, go figure, it's striped. Dying TOB, striped exhaust stud, I wonder what the third failure is gonna be?

But seriously, I want to fix this if possible, and do so without removing everything as it would be almost impossible. It's leaking bad. I think the stud will spin out. How should I try to fix this? I'm thinking remove stud, drill the hole in the manifold for the stud to go through bigger, and then get a helicoil kit and drill, tap, helicoil, install new stud, pray, and pray it works. Any better ideas? Or is this really the only option? It's gonna be a bitch trying to drill and tap straight with a manifold installed. My only concern is I'll have to not drill too far as I don't wanna drill and tap any water jackets.

Dammit, it should be throwing a rod, breaking 3rd gear, or the diff exploding or something I would actually expect to happen. Not stupid bullshit.

I still think it's fucked up that everything works perfect and then three things all fail in a short amount of time. Two down, what's the third gonna be?

patsmx5 02-07-2009 09:15 PM

But the good news is I fixed my BOV today, got my new CAI box to quit rattling, fixed another rattle under the hood, fixed a rattle in the passengers side door, and fixed the door popper in the drivers side door. So now it's kinda quiet and refined 'cept for the damn exhaust leak!

NA6C-Guy 02-07-2009 09:17 PM

Wait, so the threads in the head are messed up? Will it just not start threading, or are the threads fully pulled out/fucked? The same stud for me had a bit of an issue and cross threaded a bit, and I thought I was screwed, but I was able to hold it all just right and forced it past the messed up threads with a 1/2'' ratchet, and it pulled up and held. Im guessing since its leaking though, its not holding torque. I dont know If I would trusy helicoil. Maybe Helicoil and a dose of thread locker.

Gotta love them noises. Ive been trying to track down every noise I can find, but the damn things keep popping up. I got most of them fixed, but now Im dealing with a trans about to blow up, sounding like a race car.

Would it be possible to maybe tap the threads to the next size up without actually drilling it? Not sure of the stud size, or if you would be able to find one a hair larger in diameter, but thats what I would try. Im doing a similar thing with my old ass tractor Ive been restoring. I dont trust helicoil much, and would much rather just tap a hole to the next size and go with a new stud.

kotomile 02-07-2009 09:19 PM

Nothing's wrong, I guess he just doesn't like stripes.

patsmx5 02-07-2009 09:23 PM


Originally Posted by NA6C-Guy (Post 365068)
Wait, so the threads in the head are messed up? Will it just not start threading, or are the threads fully pulled out/fucked? The same stud for me had a bit of an issue and cross threaded a bit, and I thought I was screwed, but I was able to hold it all just right and forced it past the messed up threads with a 1/2'' ratchet, and it pulled up and held. Im guessing since its leaking though, its not holding torque. I dont know If I would trusy helicoil. Maybe Helicoil and a dose of thread locker.

Gotta love them noises. Ive been trying to track down every noise I can find, but the damn things keep popping up. I got most of them fixed, but now Im dealing with a trans about to blow up, sounding like a race car.

Either the stud is stripped or the threads in the head are striped. I turn the nut and the whole stud just spins. I suspect the head is striped being the softer metal. Helicoils are actually better than regular threads. So I really don't have a problem using them. If I was building a serious motor, I'd helicoil ever threaded part for the head bolts, main bolts, etc. I guess my only real concern with a helicoil is if I'll hit a water jacket or something drilling for the helicoil.

Koto- is it stripped or striped? I googled it before posting and striped was the more popular one I saw.

kotomile 02-07-2009 09:27 PM

Stripped. You've been slipping lately man, I thought you were a master of language.. I'm on my fifth beer tonight and I'm still making sense (I think).

But I shouldn't chide too much, I had my own experience with broken studs and it SUCKS, so I'll not add any more insult to injury. :)

NA6C-Guy 02-07-2009 09:30 PM

I know helicoil is probably stronger, but something about it always feels like a bandaid fix to me. Maybe it would be fine though. Hey, maybe you can have more fun when you go to back the stud out and it doesnt want to go that way either! Get to fight it out! j/k, hope it goes well for you, I know shit like this is alot of fun. By fun I mean a pain in the ass.

patsmx5 02-07-2009 09:39 PM


Originally Posted by kotomile (Post 365077)
Stripped. You've been slipping lately man, I thought you were a master of language.. I'm on my fifth beer tonight and I'm still making sense (I think).

But I shouldn't chide too much, I had my own experience with broken studs and it SUCKS, so I'll not add any more insult to injury. :)

Ah. Yeah, I googled it again and still couldn't figure it out. Apparently both are used interchangeably through ignorance. I know, I've been cutting back on reading the dictionary lately. Damn car would quit breaking I could get my regular 3 hours in every day.

patsmx5 02-07-2009 09:47 PM


Originally Posted by NA6C-Guy (Post 365079)
I know helicoil is probably stronger, but something about it always feels like a bandaid fix to me. Maybe it would be fine though. Hey, maybe you can have more fun when you go to back the stud out and it doesnt want to go that way either! Get to fight it out! j/k, hope it goes well for you, I know shit like this is alot of fun. By fun I mean a pain in the ass.

It's actually not a bandaid way of doing it. I guess I know all the answers to my questions. I'm gonna have to helicoil it.

Anyways, here's WHY helicoils are better. The helicoil is made of a strong, hard steel. Think like a grade 5 bolt or something. Where as say an iron block or aluminum head is softer and not as strong. Well, say I have 10mm studs in my head (no idea if that's what size they are, just guessing). If I do a helicoil, odds are I'll tap the head for 12mm or 14mm. Now the hole is bigger 'round and there's more area for threads. I screw in a helicoil. Now I put the stud in and load it. The stud pulls on the hard helicoil, and the helicoil distributes that load to the head. But now, that same load is distributed to a larger area of the head. If I keep on tightening the stud and keep increasing the load, the stud won't strip because the metal it screws into is harder than the stud is. (where as before, it was quite the opposite!) The helicoil pushes OUT around the head as you load it. The more you load it, the more it anchors itself into the head. You'll never strip the helicoil. You'll break the stud first, as it's not even 1/2 as strong as the part it's screwed into now. Hell, I guess I'll helicoil a bunch of shit this summer on my built motor.

dynokiller90 02-07-2009 11:26 PM

just use a drill stop. If you don't have one handy wrap a bunch of tape around the bit sorta like a soft drill stop. measure first drill once and helicoil that hooker.

patsmx5 02-07-2009 11:42 PM


Originally Posted by dynokiller90 (Post 365125)
just use a drill stop. If you don't have one handy wrap a bunch of tape around the bit sorta like a soft drill stop. measure first drill once and helicoil that hooker.

Good idea. I've done that like once with tape and it works great. But that was a long time ago and I completely forgot about that till you mentioned it. Thanks! I'll do that for sure. Didn't know they made drills stops. Have to pick one up one day.

18psi 02-08-2009 12:13 AM

I voted for "something stupid":giggle:

patsmx5 02-08-2009 12:21 AM

Yeah it will be something like the thermostat fall apart and clog up the radiator hose and my engine approach hyper-temps, or the intake manifold crack in half, or the harmonic balancer come apart and destroy my custom 36-1 trigger wheel setup, or the A/C compressor explode. Something of that nature.

TurboRoach 02-08-2009 04:06 AM

If you have to drill a 12mm or 14mm hole for the helicoil, wouldn't it be just as easy and secure to use a high strength larger diameter stud? Does the helicoil have some way of making the stud more secure, other than being a larger diameter? I've never used a helicoil, I'm just asking out of curiosity.

zoomin 02-08-2009 04:51 AM

What color are the stripes? jk! I would helicoil it.

18psi 02-08-2009 05:06 AM

if its just the stud thats pretty easy. if its the head I'd probably weld the hole and re-drill/re-thread. I'm a little drunk right now so tomorrow I'll read this post again adn see if it maks sense:D

bryanlow 02-08-2009 06:44 AM

Same thing happened to me. Make sure you drill & tap the hole straight or you'll have a hard time getting the manifold back on. If the holes were as deep as mine, you'll need 1-1/2 helicoils per hole.

To prevent this from ever happening again, I used brass nuts to prevent corrosion and nordlocks so I won't be tempted to overtighten them when they back out.

y8s 02-08-2009 11:48 AM

striped definition | Dictionary.com

nothin there about threads...

also... chances are the steel stud didn't strip if it's inside a nice soft aluminum head.

IcantDo55 02-09-2009 07:39 PM

Helicoil is a excellent fix, do it. There are over 1,000,000 helicoils on a 747 think there safe? The heads I have on my mustang come with all holes helicoils from the factory.

patsmx5 02-12-2009 02:57 PM

What's behind door number three?
 
3 Attachment(s)
So I leave school. It's hot, so I got the A/C on. Just aced a test in EE systems, so I'm driving kinda spiritedly. (note to self, boosting with the A/C on is sweet!) Few minutes later I'm at a red-light idling with the A/C on and all of a sudden it idles down, almost to the point that the engine was about to die. Went from a 700 RPM idle to like 350. So I turn off the A/C and it goes back to normal. How weird. It wasn't just the compressor kicking off and back on either. I just don't turn on the A/C till I get rolling and it's fine... Probably should have thought more of it, but I didn't.

Irrelevant, but I ran a mustang GT from a light to 55. Smashed him. And I wasn't even trying, shifting at 5K, A/C on, laughing all the way. :)

Five miles later sitting in a Zaxby's drive thru I hear the cooling fans come on. I get my food, pull away, and I hear yet another weird noise. Like a Whirring mixed with a clunking. Thought it was the transmission for a second but I quickly realized it wasn't. Then it stopped. Then I smell something burning, smells like an electrical fire.

Grab my fire extinguisher, pop the hood, and found this:
Note, pictures taken after I drove it home with the heater on, no A/C, light load.

Attachment 208282

Attachment 208283

Attachment 208284

I find this a bit strange. The fan motor is hot as FUCK. Like probably 300*F or hotter. Very very hot. But so is the other fan motor? The A/C fan still works, though it's been "dying" for about a year. It has like 1/4" of slack in the motor. Yet the "good" fan takes a shit? This is weird. The fan motor still turns too. It literally got so hot that it melted the fan blade off the motor shaft. There's a piece of melted plastic pictured that was stuck to the motor.

Anyways, I rewired the fans a while back so each fan had a 12 gauge wire feeding it and they shared a 30A relay fused by a 25A fuse. Strangely enough, it never blew the fuse. So the A/C fan was still running after the main fan died.

Anyways, now would be a great time to give a HUGE THANKS to fmowry. Frank mailed me a pair of low mileage cooling fans for FREE about a month ago. I got them because I needed to replace the A/C fan that was dying. Well, he sent both fans anyways. What a guy! Good thing too cause now I'll need both.

Also, it would have been smarter to put each fan on it's own power supply and relay, so that if this ever happened again, it could blow a fuse and allow one fan to remain operational. It's dumb luck that it somehow didn't blow a fuse and the other fan remained working.


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