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Discussion Starter #1
Hi guys, in the process of removing the aftermarket AC compressor and assembly I had to move a brace that was attached to the exhaust stub in the picture below.

The thread on the stud had been damaged, so I put another washer on it to try and keep the bolt off the damaged thread but when tightening it up the stud stripped. I wasn't using much pressure/torque at all. Yikes! :eek:

Now what? Helicoil? Can you even do that at an angle like this? Time for the head to come off? Sigh....



 

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Stud pulled out of the head, or nut stripped threads off the stud? If it's pulled out of the head, after the exhaust is removed, there may be enough room to get an insert in there. Or more simply, if the stud is just stripped, it can be removed with one of the several styles of stud removers and just replaced.
 

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Discussion Starter #3
Hi Gordon - thanks for the response. Turning the bolt turned the stud with little effort, so I am assuming the threads on the inside of the head are toast. I did not try to back the stud out because I was in total denial...

Sounds like my next step is to try to remove the stud and keep my fingers crossed, yes?
 

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If it turns in the head, it's stripped in the head. These can be repaired without pulling the head, but you need to create work space.
 

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Discussion Starter #5
Shhh - I'm in denial...

By work space I am assuming job #1 is to remove the exhaust manifold.

Thanks Gordon.
 

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You will need to access the stripped hole in the head, both to drill it out to accept an insert, and to install the insert and new stud. I have used a right angle drive on a variable speed drill for this, but working room is required. You should research thread inserts. While a heli-coil is Ok, there are other forms of inserts that are tougher where heat / cool cycles may cause stress on the insert threads. This can be a study in itself. I like self-locking solid wall stainless steel inserts like those from E-Z Lok and others. These cannot strip or pull out. They are hardened, and will not rust to the stud. there are others ....
 

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i got tired of pulling those exhaust studs out of my alfa head..so last year when i had the head removed..i removed all the stock studs( by the way they do not go all that deep into the head, so they are easy to pull out.) tapped the holes all the way to the bottom.. and replaced them with new studs, longer ones. and red lock-tited them to the head..and allways use anti-seize on the threaded part that the nut go'es on.. never a problem sence then.:):) you can get longer studs, just don't by alfa studs.. go to your local professional nut and bolt place, they are there,, not ace hardware.
 

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Discussion Starter #8
Thank you - good to know that I am not unique in having this problem and there is an approach to dealing with it.
 

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Alfa used bronze nuts on these studs. That way the nut and not the head was always the weakest link. I sometimes stripped the bronze nuts, but always had a bunch available. BTW use wavy washers, not split lock nuts. If you use steel nuts here you WILL eventually pull a stud out of the thread. Bronze nuts are expensive, but cheap insurance!

The latest ones are oval (self locking) but this makes them not reusable, so get a box!

The heat will always corrode the nut and the stud together if you use steel nuts. Same for the next triangle junctions at the exhaust pipe connectors. You can use SS bolts and nuts here which will not corrode together, but SS is notorious for coming loose on heat cycling.

Robert
 

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Some Alfa's I've seen (not vintage) used steel nuts in the header studs that rusted just as bad as American stuff. I, like you Robert, always go with the brass. There are some copper plated ones out there, but they are steel underneath, and the locking type. They will rust to the stud on occasion. Brass or bronze is best. ALL the vintage Alfa's used brass nuts on the header studs.
 

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Discussion Starter #11
Sourcing ideas on the correct bronze nuts? McMaster Carr? Anyone know the correct size off hand?

Thanks!
 

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Size is 8 x 1.0mm. 13mm across the flats. Check Centerline/IAP.
 

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Discussion Starter #13
Thanks Jim!
 

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tdskip.. i just took the headers of my spider, to do some work.. i have not had them off for a while, so i could not get the exact stud size i use.. well here it is.. 40 mm long x 8 mm.. and the exhaust stud has a allen key to thread it in ' all the way in' not part of the way.. just get a 8 mm tap.. and chace the tapp all the way to the bottom. clean, and insert the exahust std into the head.. with the allen key.. use lock tite on the thread that go into the head..and lots of anti-seize on the treads,, and you will not have any problems.
 
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