Bent exhaust manifold stud - options?

[Healey3000]

Hi,

 

I bought a used head that has a bent stud on #3, lower.  I can't tell if it is bent only on the part that's visible or whether it has also damaged the threads in the head.  The usual technique of using locknuts isn't budging it and I'm afraid to force it.

 

How best to remove it?  A stud puller?  Some other tool?  If the head is damaged, can this be fixed with a helicoil or insert?  I can't see any distortion on the face of the head so I'm hoping the damage is minor.

 

Thanks!

[Simeon]

The stud is already trashed and the head is off the car. This is an opportunity! You can get your biggest and ugliest tools on it. If it has that good of a grip on the stud then the head is unlikely to be damaged. Certainly it can be repaired with a helicoil or similar if it was. 

 

Get a big pair of Vise grips or even a small pipe wrench that will really bite into it and grip. I have one of those stud removers with the rotating knurled cam but rarely use it. I would give that a go too but wouldn’t buy one specially for this job. Chemical warfare should be considered too and perhaps some delicate heat to be applied to the stud. Most likely it has some heavy duty Locktite on it and you might need some help to break that down. 

[Healey3000]

Simeon,

 

Thanks for the positive outlook .  I do hope you are right!  I may take it to a muffler shop where they usually have nasty-looking stud pullers designed for rusty exhausts.  I'm reluctant to apply heat at this point.

 

[02Pilot]

Spin an M8 nut on and then MIG weld it to the stud (in effect creating a bolt), then loosen with a socket - it should spin right out. The heat of the weld will radiate down through the stud and loosen up the threads without any risk to the surrounding area.

[Jimmy]

1 hour ago, Healey3000 said:

Hi,

 

I bought a used head that has a bent stud on #3, lower.  I can't tell if it is bent only on the part that's visible or whether it has also damaged the threads in the head.  The usual technique of using locknuts isn't budging it and I'm afraid to force it.

 

How best to remove it?  A stud puller?  Some other tool?  If the head is damaged, can this be fixed with a helicoil or insert?  I can't see any distortion on the face of the head so I'm hoping the damage is minor.

 

Thanks!

 

There are thread locking compounds for which the instructions explicitly state that they release only with heat applied. I've seen them take metal with them when forced. So use heat. If you really don't want to, spin the on past the end of the stud, smack the tip of the stud to mushroom the threads so the nut can back off, and remove it with an impact wrench. But really, just use heat since you don't know why it won't come out. 

[Healey3000]

Good news!  I went to a local muffler place and he gave me a song and dance about needing a lot of time to do it and that I should leave the head with him.  Right!

 

Then I drove through an area that has a bunch of little repair shops and saw a sign that said "European" so I said, what the heck, let me try.  The very kind gentleman there took a look at the head in the trunk and said, let me give you the extractor and you can do it yourself in the trunk of your car.  Out it came with minimal effort and it's bent like a banana.  Fortunately, it looks like there is no damage to the head.

 

For those of you in the Bay Area, Here's their business card.  Husband and wife seem to be running the place and while I don't know what their work is like, they have been in that location for thirty years and their service bay had a bunch of nice cars in them.  I know I'll be going there again.

 

Thanks for the help and suggestions.  Special thanks to Simeon for the positive vibes!

[irdave]

And just to add on putting them back in.  When I recently rebuilt an engine using the 1.8i head with new studs, the fit was so tight I broke a stud trying to get it to screw in- so just be aware the fit might be a little too tight and need to be cut some.

[02Pilot]

29 minutes ago, irdave said:

And just to add on putting them back in.  When I recently rebuilt an engine using the 1.8i head with new studs, the fit was so tight I broke a stud trying to get it to screw in- so just be aware the fit might be a little too tight and need to be cut some.

 

If the fit was that tight something's wrong. Definitely chase the threads with a tap before installing studs. New ones with either an external or internal hex end are available, making the job a lot easier. Blue Loctite will keep them in place.

[Hans]

There may have been residual sealant from previous replacements. Thread chaser is your friend. The upper row of studs needs some sealant to prevent oil seeping.

[Jimmy]

1 hour ago, Hans said:

There may have been residual sealant from previous replacements. Thread chaser is your friend. The upper row of studs needs some sealant to prevent oil seeping.

 

I can confirm having difficulty with stud looseness and oil seeping on the top row of studs when I replaced my manifold gasket. After trying "thread sealant" that never really harderns, then blue permeatex thread locker, I finally had good luck with Loctite 243 Oil Resistant blue thread locker. It's not as readily available at your FLAPS but it's worth finding the right thing the first time. Be sure you shake-up/knead the tube before applying and squirt a little bit out the tip before using it. Like ketchup or mustard ?