EXHAUST MANIFOLD STUD

[Ed D.]

I was pulling off the old exhaust system on my 327/300 when one of the bolts broke off at the nut. This was just below the heat riser. Are these studs pressed in ? ....screwed in ? or ??? I looked in the 1965 assembly manual but it showed nothing. I see new bolts listed in various catalogs but it doesn't say anything about how to get the old one out or the new one in! I couldn't find this posted before on the forum. I can't be the only one this has ever happened to ! ...Thanks ...Ed

[Jean C.]

EXHAUST MANIFOLD STUD

Ed, the steel studs are threaded and screw into the manifold. After you get the broken stud out of the manifold and install a new one, use bronze nuts on the steel studs and you will not have problem with seizing the next time the exhaust is disassmbled.

Charlie
#40193

[mikemccagh]

Re: EXHAUST MANIFOLD STUD

If you've not had experience heating a manifold (assuming the stud is partially sticking out of the manifold), probably better off taking it to a machine shop for extraction. If its broke off flush with manifold, it'll need drilled and an attempt with easy-out made. may need to drill and tap. good luck, mike

[Ed D.]

Re: EXHAUST MANIFOLD STUD

Thanks Mike and Charlie ! The stud has about 2 inches left on it. So I guess I will use a set of visegrips / penetrating spray and try to unscrew it. Mike you mentioned heating the manifold. Is that only if the bolt was broken off even with the manifold? OR ... is that necessary in all cases to get it out? Thanks ... Ed

[mikemccagh]

Re: EXHAUST MANIFOLD STUD

I doubt the pentrating oil will allow for stud removal. it all likelyhood, the stud will probably shear off at the manifold base, then you'll have a bigger hassle getting it out. I would heat the manifold area surrounding the stud cherry red with oxy-acetylene torch, quickly take vise grips to stud before manifold cools. even this approach has resulted in stud braking off flush, then you'll have to drill/easyout or drill /tap. good luck, mike

[Dennis C.]

Re: EXHAUST MANIFOLD STUD

Ed - I believe I would follow Mikie's advice. Take it to a pro and then ask if you can watch and learn. If you make too many mistakes on this learning curve, you can end up looking for a replacement manifold. Play it safe. Best, Dennis

[Ed D.]

Re: EXHAUST MANIFOLD STUD

Thanks Everyone ! I think I'll bite the bullet and bring the manifold in. I thought replacing the studs was a home project.... guess not! Better safe then sorry. .....Ed

[Ted S.]

Re: EXHAUST MANIFOLD STUD

The machine shop I go to would heat the stud cherry red and then touch it several times with parafin where it's screwed into the manifold. I know it sounds backward on the heating part put they have been able to remove broken off studs in old two piece 6 cylinder exhaust/intake manifolds, heads, exhaust manifolds, etc. The studs/broken off bolts seem to come right out after this. I'm not sure exactly why it works, but I've witnessed it several times. Hope this helps.

[Dick W.]

Re: EXHAUST MANIFOLD STUD

Dr. Mikie and Dipstick are right. If you are not familiar with heating to remove seized bolts you are way ahead to take it to a professional. I have been doing this for over 40 years (am I that old?) and still have trouble with some broken bolts.

Never Seize compound is a would be good to coat the threads with. It will ease the removal the next time without having to resort to head, drills, extractors, etc.

[Roger Legge]

Re: EXHAUST MANIFOLD STUD

I can not remember the name of the machine/technique, but I have heard of machine shops having a machine that removes the material of a stud that is broken off flush. Something along the lines of a plasma cutter, but much, much finer/smaller and it essentially melts/burns the stud in a very controlled way. I would guess careful use of a tap would get the rest of the stud out.

Roger
#36316

[Ed D.]

Re: EXHAUST MANIFOLD STUD

Thanks Roger... I'm lucky (I think) I still have 2 inches and some thread at the top of the bolt ......Ed

[Terry M.]

Electo Discharge Machining (EDM) *NM*

[Roger Legge]

Re: Electro Discharge Machining (EDM)

Yep! Just found the info. Wire electrical discharge machine, or EDM for short. Uses an electrical spark delivered by a fine wire to cut through any material that conducts electricity.

Roger
#36316

[Ronnie Robertson # 36786]

Re: Parafin Works...

Parafin or plain old candle wax applied to a heated part works well for unfastening frozen bolts or nuts. Just heat the bolt or nut with a propane, mapp, or any good heat source and apply the wax to the parts. Promptly apply constant force and as soon as it moves, move back and forth until it is free. Repeat if necessary. I think I saw this idea on this board...
Good Luck

[Lonnie Johnson]

Re: EXHAUST MANIFOLD STUD

Smart move. That's exactly what I did with my 62. I've drilled broken/seized bolts out and retapped them before, but didn't want to take a chance with these puppies! BTW, make sure the guy you take them to is a real "Pro", not a bubba clone. Makes a mess if they get off center when they try and drill it out. I quizzed the guy that did mine about how he would do it and suggested he use his milling machine rather than an old drill press he had in the shop. He didn't like it too much, especially with me standing looking over his shoulder, but he must have needed the business enough to put up with my eccentricity.