Exhaust Manifold Stud Sheared

[jforest1]

'73 Cuda 340 with factory exhaust manifold.

Because my exhaust manifold was the biggest eyesore under the hood and was covered with rust, I decided to put it in the blasting cabinet and repaint.  I bought a new set of gaskets off of year one and a hardware set for them in preparation for it.

After removing the left side exhaust manifold, I was left with two studs--the forward most and the back most.  Since the hardware kit included only 4 of these for both sides, and I had already removed the inner two, I left the outer two as is and moved on to the right side.

I removed most bolts no problem, but ended up shearing off the forward most stud.


  Yikes!  But before I got out the left-handed drill bit, I wanted to go ahead and test a theory.  I put a couple of nuts on the back-most stud on the right side and began backing it out.  After a bit, I heard a bunch of dripping.  I reversed direction and worked it back end, looked under the car and nothing...

So:
1.  what was the dripping?  i assume engine oil...
2.  where was it dripping into?
3.  if i drill out the forward one that i sheared off, will I have the same problem and should I drain the oil or whatever in preparation.
4.  why did the kit include 4 studs (2 for each side), when it appears it need 8?

a note:  i have the car up on ramps in the front


Thanks in advance!

JF

[IMNCARN82]

It would be coolant.  The end bolts on each side goes through to the water jackets.     Use two per side on the ends. The rest are bolts.  R/T

[Milkmann]

It would be coolant.  The end bolts on each side goes through to the water jackets.     Use two per side on the ends. The rest are bolts.  R/T

 

What he said.

 I replaced the studs on my 340 when I put headers on, just to make sure the threads were full depth and hopefully insure that what happened to you wouldn't happen to whoever worked on it next. I also used anti-sieze and stainless nuts when I put it back together.

To get your broken stud out, if you have access to a welder lay a flat washer on top of the broken stud and weld it on, then weld a nut to the washer. The heat from welding helps to loosen the seizing, and then you can put a wrench on the nut and hopefully turn it out. If it doesn't come the first time, keep trying. The weld doesn't stick to the cast head very well, you can use more heat than you might think.

I learned this trick off a farmer message board I view, and I have used it several times. It works more often than not, if it doesn't, you can still drill it out.

[jforest1]

Thanks for the info guys.  I had some unexplained bolts in the kit and that makes sense.  The previous rebuild of the engine put all studs in.  I don't have access to a weld so I'll attempt the left hand drill bit method first.  Adding anti-seize lube to my list as well as a catch bowl for draining the coolant.

JF

[Strawdawg]

On the ones going into the water jacket, be sure to use a thread sealer on them in order to avoid a leak

[jforest1]

On the ones going into the water jacket, be sure to use a thread sealer on them in order to avoid a leak

I apologize for my ignorance on the subject, but I assume teflon tape is out of the question given the heat levels of the area?  Point me in the right direction, what am I looking for here?

JF

[Chryco Psycho]

teflon tape will work fine or the liquid teflon pipe dope

[jforest1]

Okay, an update.  I drained the coolant and removed 2 of the remaining 3 studs.  The sheared one still is sheared, but I did go ahead and remove the alternator so I have some space to work when it's time to get it out.

For the 3rd of the remaining studs, I can't seem to get a nut on to it, so I am unfortunately stuck. 

I'm not sure if there was another way, but I kinda figured out that two nuts with a lockwasher in between creates enough thread friction that I'm able to remove the studs by turning the innermost one. 

Is there another way? 

If not, is there a tool that will tap studs similar to how i can tap a nut?  I need to be able to get the stud's starting threads correct.

If not, what do I do in this situation?  Cut off the messed up starting threads with a dremel?

JF

[Milkmann]

I took my studs out by clamping a Vise-Grip onto them. I have had poor luck with locking pliers that didn't say "Vise-Grip" on them. There are tools made for removing studs but it wouldn't be worth buying a tool for one stud.

Often a nut will start on buggered threads if you can get some pressure on it, either have the nut in a shallow socket or stack up nuts in a deeper one so that the one you want to start has no where else to go. Push hard while turning. A thread cutting die will clean up the threads if you have or can borrow one. There are thread-cleaning tools available but I have never used one.

Now you have another reason to curse the last mechanic who did not use anti-sieze.

Good luck. Keep at it, it will come.

[Jesus H Chrysler]

Some auto parts stores have rental tools.  I rented a set of stud pullers a while back and they sure were handy.  They look like a socket with cam works inside to grip the stud.  The down side is if they are STUCK stuck they just spin or worse shear the stud like you already have.  I've done the 2 nuts locked together thing and it works, but you have to be careful of side loading the stud which can shear it.  The stud pullers help with the side loading.

My 2 cents to add is HEAT.  If you have access to an oxy/acetalyne setup it can do wonders for helping out the stuck studs.  Just be careful to keep the heat near the stud you don't want to warp the head.

[the_engineers]

If you haven't had much experience with an oxy torch, I'd advise against it...you can make things much worse very quickly with an inexperienced hand. Try a MAP torch to get the heat you're going to need.  You'll want to drain the coolant beforehand, because anything that works is going to leave you with a small piece of metal (potentially very hot) and coolant pouring out of the motor.

Some people have had success touching a piece of wax to the base of the broken stud.  The heat will/should suck some of the wax into the threads, helping to loosen everything.

[jforest1]

I've already drained the coolant, so I'm good there.

I've applied some Blaster (made sure that it ONLY was applied to the stud), tapped the stud on the head with a hammer (actually, a nut just proud of the stud).  That's the only nut I can get on it though--tried like 5 others.

So what's the explanation on the heat?  If heat expands the metal, wouldn't that lock up the threads tighter? 

JF

[Matt70]

The heat expands the metal around the stud helping to free it up. Works very well

[Strawdawg]

I've already drained the coolant, so I'm good there.

I've applied some Blaster (made sure that it ONLY was applied to the stud), tapped the stud on the head with a hammer (actually, a nut just proud of the stud).  That's the only nut I can get on it though--tried like 5 others.

So what's the explanation on the heat?  If heat expands the metal, wouldn't that lock up the threads tighter? 

JF

he said near the stud...heat the area around the stud..not the stud directly   

[72rtchallenger]

if you use heat go around the stud trying to stay off the stud itself ,,if you use the left handle drill bit make sure and use a small punch first to get a spot in the very center of the stud so you start the drill bit in the center as close as possible,,because if all else fails you may end up drilling the stud out and re-threading(tap and die set) the hole,,and if you go that route (as a last resort )you want to be drilling dead center,,and then use drill bits getting the hole just alittle under the size of the stud but very close and then  a tap can be used to clean out the metal left in the original  threads,,and that will take alot of patience and careful drilling,,I have done this before with great success but its not easy,,of course it would be easier that route if the head was pulled