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Thread: How to- exhaust manifold

  1. #1
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    How to- exhaust manifold

    I was surprised there is no how to on this. It's fairly straightforward if everything goes right. The number one rule is don't break a stud. This will multiply your work several times. Points on making that happen.

    I'm not going to go into the removal of muffler, cat and crossover. It's all pretty straightforward. So you've done all that and now you are at the manifold nuts.

    First, a note on penetrant oil. Everybody has heard that you spray your favorite penetrating oil a week in advance. I've heard this and done this on many occasions. I have yet to see any evidence that it makes any differnce. I believe the rust/corrosion is too thick to penetrate. I guess that is debatable, but for this job, don't even risk trying to remove the nuts by this method. (Especially if your manifold hasn't been off for many years)

    As an experiment, I doused the nuts several times a week before with "PB Blaster". I purposely picked the easiest nut/stud and attempted to remove it. Broke the stud with very little force.

    The best method (and what I did for the rest of the nuts) is heat the nuts cherry red with an oxi torch. Before they cool completely, remove with a socket. All of the rest of my nuts came off easily except the rear most nut. It broke the stud. I believe the stud was allready compromised and/or I didn't quite get it heated as good. While I did this step with an oxi-acetylene, I believe a propane torch could be used. You are trying to get the nut red hot, but don't worry about heat going to the stud. (You will be heating this later anyways)

    So now you have the manifold off and maybe you didn't break any studs. The next job is remove the studs. You might be tempted to install a new gasket and be done with it. If your studs are less than a couple years old, I might agree. For anyone else, replace the studs. How to remove them? I tried two different methods on the unbroken studs and both worked. Method one involves heating the stud cherry red several times. Each time letting it cool alittle in between. What you are trying to do here is break the corrosion lock between the stud and the head.

    Once you do this, you can remove the stud your favorite way. (Double nut, stud extractor or just vicegrips.) Of course, the stud extractor is great and that's what I used, but vice-grips will get the job done.

    The second method I tried to heat the stud, I found on u-tube and is very interesting. You take spare battery and jumper cables and ground the engine block. Then clamp the hot cable right on the stud. Obviously, this is a direct short and sparks some and then starts making things hot. The battery, cables and especially the stud get hot. It may be that the stud gets hottest right at the corrosion lock. I don't know, but it worked just as good as the oxi torch. I don't think it's good for your battery or cables, but if you don't have a oxi-torch, it works. Note, I had the cable hooked up for about 30 seconds.

    If this all went well, your ready to assemble. But what if your best efforts failed and you broke a stud flush or under flush with the block?

    There are multiple ways to deal with this also. Here's what I had great success with. On the stud that I previously told you I broke as an experiment with the penetrant oil, I center punched it. Don't be afraid to centerpunch it hard. (It might jar it loose) Then I drilled it completely through with a 1/8" bit. At this point, some people might try an "easy out". I have never had good luck with them on small bolts/studs and I wouldn't risk it here. If you break the easy out in the stud, now you have a hardened chunk of metal stuck in there. (I'll talk about this at the end of the post)

    Anyways, after you have a hole in the stud, get a slightly bigger (3/16") drill bit and start drilling. Then I went to neerly the size of a tap drill for 7mm and drilled again. You need to be careful here because the stud remnents might break loose and try to lock up the drill. After that, just run a tap down to clean up the threads. If your original hole was close to dead center, it should be fine. If you were off a bit, you might need to helicoil it.

    On to the "hard to get" stud. I had to use a right-angle drill to get in there. It was impossible to even see if I was centered in the stud. So I made this simple little guide.

    dscn2343.jpg

    It's just a disc with a 1/8" hole in it. I put a small shoulder on it so it stayed center. I also made a small piece of aluminum to bolt to the next hole. That way I could hold it in while I was drilling.

    dscn2341.jpg

    It worked great and I was able to drill straight through the stud. After I had that hole, I used a "left hand" 3/16" drill and guess what? It grabbed and backed the stud right out.

    dscn2344.jpg

    It really wasn't that bad of a job, but again, don't break any studs to begin with and you will be way ahead.



    Oh, there's something else I need to mention that allot of people don't know about. If you break an "easy out" or a drill bit and it's stuck in the stud, all is not lost. You might think the easy out or drill bit is a harder material then anything else you can drill with. Not true. They make very small holesaws that are diamond tipped. They will go through anything. I know what your thinking. Hole saw? Yes, I used a 1/4" hole saw to drill through an easy out and a 3/8" bolt one time. It was amazing. The one I used was made by Lennox.

  2. #2
    Senior Member Bitsyncmaster's Avatar
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    I like that idea to use a battery to heat a stud. Never heard of that before. I would guess most of heat would be right at the threads in the block. You got me thinking maybe a low volt heavy amp transformer would work. Power the 120 volt side through a variac so you can bring up the current slowly.
    Dave M vin 03572
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  3. #3
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    Quote Originally Posted by Bitsyncmaster View Post
    I like that idea to use a battery to heat a stud. Never heard of that before. I would guess most of heat would be right at the threads in the block. You got me thinking maybe a low volt heavy amp transformer would work. Power the 120 volt side through a variac so you can bring up the current slowly.
    I'm not an electrical guru, but I was wondering if I could just hook my stick welder to it and switch it on? I could dial up the amps slowly. If/when I do the other side, I'll try it.

    Edit, I wouldn't want to wreck up the stick clamp.

  4. #4
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by Helirich View Post
    I'm not an electrical guru, but I was wondering if I could just hook my stick welder to it and switch it on? I could dial up the amps slowly. If/when I do the other side, I'll try it.

    Edit, I wouldn't want to wreck up the stick clamp.
    We think alike. I just thought of that when I was in the garage and saw my TIG welder. My TIG can do stick welding and adjustable amps.

    Just clamp on the cables, set the amps and throw the power switch. Maybe 10 seconds at 100 amps is a good start.
    Dave M vin 03572
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  5. #5
    Administrator Ron's Avatar
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    $.02

    A propane torch will heat too slow.

    Have your tools ready, heat the nut, take it all the way off without stopping unless it gets fairly tight. Do NOT turn it back and forth "to clean the threads".

  6. #6
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    Quote Originally Posted by Bitsyncmaster View Post
    We think alike. I just thought of that when I was in the garage and saw my TIG welder. My TIG can do stick welding and adjustable amps.

    Just clamp on the cables, set the amps and throw the power switch. Maybe 10 seconds at 100 amps is a good start.
    My TIG is like yours. (Can do stick) I don't have a MIG. It's one of the few tools I don't own. There's a number of tricks you can do with a mig for removing nuts/studs. It's hard to justify buying a mig for that. I can do all the welding with a stick or a TIG.

  7. #7
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by Helirich View Post
    My TIG is like yours. (Can do stick) I don't have a MIG. It's one of the few tools I don't own. There's a number of tricks you can do with a mig for removing nuts/studs. It's hard to justify buying a mig for that. I can do all the welding with a stick or a TIG.
    I also have a MIG. It's nice to weld with one hand and very fast for a long weld. Making spot welds to hold things in place is also useful. I do have an electrical spot welder also but don't use that much.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  8. #8
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    Quote Originally Posted by Helirich View Post
    I'm not an electrical guru, but I was wondering if I could just hook my stick welder to it and switch it on? I could dial up the amps slowly. If/when I do the other side, I'll try it.

    Edit, I wouldn't want to wreck up the stick clamp.
    If you use a welder, just weld a nut onto the stud. The heat from the weld will heat the stud and also give you a way to put a wrench/socket onto the welded on nut to back the stud out.

    Also, they make an inductive heater just for loosening stuck nuts and bolts: https://www.amazon.com/gp/product/B0...=A3BIS2KX0GYGM

    You could probably get them cheaper on ebay.

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