The Stovebolt Site Forums The Shop Area Engine Shop Bent Stud on '54 235 Exhaust Manifold - What to Do?

After finally figuring out that the manifolds that came on my project's '54 235 were actually for a 216, I found and have cleaned up a correct set for the engine.

As I was getting ready to bolt them to the block, I noticed that one of the studs on the exhaust was bent and would not allow the exhaust flange plate (or whatever the correct name for that part is) to slip over the studs.

I have chased the threads and they are good...but the bend the the stud to the rear is just barely too great to allow the plate to slip over it.

Do I need an acetylene torch and a hammer to urge it a little straighter, or do I have to replace it? Any other suggestions as to how to make this work? (I don't have an acetylene torch, but could take the manifold to a shop if needed.)

Thanks!

I would suggest you replace both it if you can them out. Chase the internal threads and then install the new grade 8 studs coated with neverseize.
Coat the threads for the flange also before you install the nuts. It will save you a lot of headaches 20 years from now when you rebuild it again.

Don

Since it is not mounted, I would replace both. Just double nut the stud and break them loose.

Id try loading the bolt with nuts and bending it straight in a bench vise.

Replacing both studs with new is probably the best way to go. Looks like the left (forward) one has some damaged threads. But full disclosure: I've used Guiltplayer's redneck recommendation of bending the existing stud back to sort of straight.

Should you decide to remove the studs, chances are, if you try to muscle it out, it will snap off right at the manifold. This can turn a relatively simple job into a much bigger headache.

I would strongly recommend heating the cast iron around the stud until it's a light cherry red. This helps to expand the cast iron, loosening its grip on the stud. Once hot, carefully try removing the stud.

If it doesn't move easily or feels completely seized, douse it generously with a liquid penetrating oil. Kroil is excellent if you have it, or any equivalent quality penetrating oil will work. Let it soak in for a bit. Then, try heating and removing it again. Repeat this entire process (heat, attempt removal, penetrating oil if needed) as many times as required until the stud starts to loosen.
It takes patience, but this method significantly reduces the risk of breaking the stud and saving you from potential drilling and extraction.

Good luck with the repair!

Thanks for the input!

I will let you know what the result is...

If you plan on removing the bent stud, I recommend that you heat stud with a Mapp gas torch until it turns red where the bend is and straighten it with a piece of iron pipe which just fits on the stud.
At this point, I would look it over good to determine if the threads where the nut will ride is still sound.
If you determine that the threads are too far gone, at least now you have a straight stud to work with to put the proper force on it to remove it.
I'd double nut the very end of the stud, heat the manifold and the bolt, then strike the end of the nut with a hammer.
I'd then very carefully try to turn the stud clockwise until you feel the slightest of movement, then carefully turn it counter clockwise until it moves slightly.
Now you cam turn it back and forth as though you were using a tap to tap threads. Once you get some movement in both directions, penetrating oil will be able get in there and do its job.
Do all of this like you have all the time in the world.

I have removed quite a few studs that were stripped or what have you. I always heat the manifold. It is cast and will expand in a hurry. I don't like twisting on the studs too hard cold for fear of breaking one off. Drilling out a broken stud isn't fun.

Candle wax (paraffin) is a much better penetrant for breaking loose rusty bolts in cast iron than PB Blaster, or other penetrants. Get the stud as hot as possible with a Propane or MAPP torch, and touch a candle to it. It will SMOKE and might even flame up. Once the wax has penetrated the threads, double nut the stud tightly and work it back and forth with a long breaker bar and a deep socket. Patience! It will eventually break free and unscrew without any damage.
Jerry

Wise advice Jerry, glad to see Ya posting!

Don

I don't have much of a choice, Don- - - - -I'm on a week's worth of "limited activity"- - - -no driving, and I'm not supposed to lift over 10 pounds! Pounding computer keys seems to fit those requirements! There's some "cardiac rehab" on the horizon, also.
Jerry

Since I have a limited budget but have seen a couple of places where a hotter torch than my propane unit would have been handy, would it make sense to purchase a small oxygen/map-pro unit from Tractor supply for about $100? The internet says that it burns at about 5400 degrees. (oxygen/acetylene supposedly burns at about 6300 degrees) Are the small oxy/Map-pro units decent to use, or are they more like toys than tools?

Propane should get the manifold hot enough to get studs out of it. But then again as the saying goes, one can never have too many tools. But i have no experience with oxy/map-propane torches, having invested in oxy/acetylene quite a while ago. Back when I was sweating a lot of copper pipe, we used air/acetylene, but have recently done that up to 1" size with a plain ol propane torch.

I`ve replaced them too. Snap them off and drill it out. I guess I am a redneck, more of a cracker but,
some of you guys seem to want to tell people to do the hardest thing to repair. Why IDK. Is it ? I know you guys know alot...but geeez.
If you have to replace the studs, drilling them out to the proper size replacement is very easy.

Heat OR penetrant will aid the removal. If you heat it above the boiling/vaporization point of the penetrant, wait for it to cool and then add the penetrant.

Agree, but not too cool as the heat in the manifold will help draw the penetrant in.

If you choose the cut/drill/tap method be very sure the first hole you drill (a small one) is exactly on center. It's almost impossible to get an off center hole straightened up again. "Been there- - - -done that"
Jerry

If you are going to try the common "nut and bend" method first I would get a coupler nut. It's a long nut. some hardware stores have them or you can get them from McMaster Carr in about 23 hours. I don't know how they deliver so fast. If you are going to heat the manifold cool the stud with water before turning to contract the stud or use freeze spray. You might even hear it crack loose. JMHO.

I figured that I would let you all know that I took the risk of trying to straighten the stud enough to function by using the simplest method...a hammer.

After reading the comments above, I sort of expected to break the stud and I didn't want to break it off at the manifold. So, I put a couple of washers on it, then cranked down a couple of nuts pretty firmly hoping that if I did break the stud, there would be enough of it left sticking out of the manifold to facilitate removing the rest without having to drill it out.

I put a couple of nuts on the stud above the apparent center of the bend and gave it some modest impacts with a hammer. Taking it a little at a time, it was eventually straight enough to get the header pipe flange on without issue.

Now I have to ask another basic question...

In the attached photo, does the gasket on the right get used in my application? If so, where? I would assume that the donut-type gasket goes between the manifold and the header flange. Part of me guesses that the flat gasket is for a different application...but I have been very wrong many times!

It depends on the shape of the pipe, and the hole in the manifold. The donut gasket is used if there's a chamfer on the inside diameter of the manifold port, and a corresponding taper in the exhaust pipe. Earlier applications had a flat flange welded onto the pipe, with a flat surface on the manifold. Use whichever gasket fits the specific application you have, not both.
Jerry

Thanks Jerry!

Things are shaped appropriately for the donut gasket.

I would probably have been more worried about breaking the manifold than the stud. A broken off stud is fairly easy to fix - a broken manifold, not so much.

yeah ,percussion is not ideal for that. But it worked i guess.