Exhaust Manifold Removal BBB

Discussion in 'Wrenchin' Secrets' started by Electra man, Sep 5, 2018.

  1. Electra man

    Electra man Older and Slower

    As some of you have seen I have a 67 Electra. It had some exhaust chug when I bought it and I saw the original y pipe was starting to poke through in spots and make noise. I had my dual exhaust put on and low and behold there's still a chug. The exhaust manifold gasket has blown out at the rear of cylinder 8 which I believe is common. My problem is this manifold has never been removed in 51 years. What were originally 9/16ths bolt heads have been reduced to fitting in a 14mm socket. What would be the best approach to removing it, torch off the bolt heads and remove the remains of the bolts like studs or actually attempt to remove the bolts with heat from a torch and a rachet? I know it would be much easier to do this with the head on a bench but that's not an option for now. The manifold is in good shape with no cracks. I don't want to put headers on it in any way before it's even suggested. Were not talking about a muscle car here, besides these 67 BBB manifolds are some of the best flowing cast irons that were ever designed. BTW why didn't the designers put a bolt there? That spot takes all the exhaust pressure when it's cold! Ah but for 1 more bolt it would still be quiet. - Bill
  2. telriv

    telriv Well-Known Member

    That manifold was off previously as Buick didn't use gaskets. Have the face of the manifold surfaced. IF you do use a gasket get Rem-Flex.
  3. yachtsmanbill

    yachtsmanbill Well-Known Member


    #8 by the AC evaporator housing? Heat usually helps do the trick, but that one is a bassturd. If you have access to a small brazing tip, make it really short and get the blue flame right in and on the bolt head. Youll hafta be ready to get on it since the flame will still be a foot long. Make the head almost white hot. Dont get in too close in case it "POPS" which may blow the white hot steel away and make more grief. You can also hang some saturated with water heavy beach towels around the area to protect wiring and the evap housing etc.
    If you can get a punch in there while its still pretty hot and give her a good smack that may help shock it. Try tightening it a hair, then loose a hair, back and forth increasing a tad each time. You may also have good luck with one of those new sockets for stripped bolt heads... looks like a spline in the socket.
    Dont be disappointed if it breaks. That has a tendency to happen all too often. If you manage to get the manifold off, chase the threads with a bottom tap with lotsa P-oil and blow debris out frequently with air. The 2 mating surfaces need to be clean. I used a 14 inch long MILL BASTARD file on mine with REMFLEX gaskets on my headers and plenty of anti-seize on the bolts. Good luck Pilgrim! ws




    Last edited: Sep 5, 2018
  4. yachtsmanbill

    yachtsmanbill Well-Known Member

    Even like this it still SUCKS... ws

  5. Electra man

    Electra man Older and Slower

    Thanks for building up my confidence Bill!
    Tom this has never been off. I was only assuming it was a bad gasket. If it doesn't have a gasket why is it leaking? Could the manifold be bad in a spot I can't see? Cracked, warped, ect? - Bill
  6. buick64203

    buick64203 Just plum crazy Staff Member

    And now for the dissenting opinion- any "through" bolts wont come out. They WILL snap with 100% probability not matter how much heat you put to them. And they will snap flush so there is no chance of clamping vice grips to them, which wouldn't help anyway. You'll have to drill them out and the only way your doing that is with the engine out of the car. My friend had a trick where he blasted the snapped ones out with a torch for me. But I took the engine out for him.

    Any lesser attempts, just don't even bother
    Smartin likes this.
  7. Electra man

    Electra man Older and Slower

    Thanks Jason, EXACTLY what I didn't want to hear but I don't doubt a word of it. Even the guy who built my exhaust system doesn't want to touch this repair while being paid by the hour! He's done this before and swore he would never do it again "for all the money in the world" which really put a damper on my new exhaust system joy. - Bill
  8. yachtsmanbill

    yachtsmanbill Well-Known Member

    Didnt wanna go there but JC has a point; to a point LOL. Burning out a steel bolt from a cast iron threaded part isnt very difficult. ACCESS is the trick. The rust on the threads acts as an insulator, and cast iron wont burn with a torch. If the stud is flush with the head, you get it almost white hot (again control is the issue here) and bump the oxygen lever. PFFFFT and 90% of the steel bolt is out (put the hair out after youre done LOL). What remains can usually be picked out then cleaned with a tap. Broken/burned off studs in the manifold to pipe joint work the same way. It even pretty easy to slice a muffler off the pipe(s) keeping that dead air space between the two pcs.
    This whole process is dependent on the manifold being off. So in the natural order of progression, try the bolt, or it breaks leaving you with a stub to cut off CLOSE to the manifold or a little to play with until its' all mungoo'd up, down to the cylinder head. Now you try to burn the bolt out in place or pull the head(s) then you can bolt the manifold back on to use as a guide to drill it. Its all part of Darwinism'. You can then have the pipe surfaced by a shop or put it on the belt sander. Thats a whole different issue.

    Just to be clear is this the upper bolt (exposed above the manifold) or the lower bolt that is in a bottom threaded hole? Quit the gripes and drop yer pipes LOL... ws

  9. buick64203

    buick64203 Just plum crazy Staff Member

    I used to be young and full optimism once.....:D
  10. Electra man

    Electra man Older and Slower

    I haven't worked with a torch regularly for over 25 years so I'm going to classify myself as a novice at this point. I wouldn't attempt that without practicing on several other items over time. Not the kind of thing I'd want to ruin. Back when I worked on printing equipment we had a method of drilling out broken and rusted bolts to the point we were just above the thread and start them out with a dull starter tap. Then we would peel it out with a sort of dental tool. It comes out like a helicoil. Then clean and chase the threads. This will have to be done with the head off though. You don't have the option of using a torch in a print shop. Between the inks, solvents and paperdust it would be an unpleasant experience. - Bill
  11. buick64203

    buick64203 Just plum crazy Staff Member

    That's basically the way I do it. Center punch it then start with the smallest bit. Keep incrementally drilling the hole larger. If you get off center, just angle the drill bit and re-center. Keep going till you get as close to the old threads as you dare. You can try hitting what's left with a chisel and try and collapse the broken bolt into itself. Once that happens the bolt, or what's left of it, gets loose and you can almost unscrew it out
  12. gsgnnut

    gsgnnut Well-Known Member

    Been there. As others said they are not coming out without a fight. Heat is a necessity for minimizing bolt breakage. Penetrating oil patience hammer and punch also helpful. Motor may need to come out . I got lucky a few years ago with same problem but motor had been done 15 years prior and antiseize was used and it still took 8 hours to free the boltswithout breaking them. Not so lucky when breaking down the original motor. Half broke even with all the tricks. Drilling and heli coils were necessary
  13. Electra man

    Electra man Older and Slower

    Once I put the car up for the winter all the work starts. I have to do the manifold a complete cooling system and the timing chain, all original parts. There is a good and a bad with a low mileage car this age. One is it's all original and only that way once. Used lightly and stored well in it's long lifetime. The other thing is it can't stay that way if you plan to drive it. I've already done the suspension so when the above list is finished shes ready for long distance trips. - Bill
  14. yachtsmanbill

    yachtsmanbill Well-Known Member

    Thats where having the head on a bench helps, using the manifold as a guide. One or two centering bushings and yer home free. FWIW, cast iron drills like aluminum. If youre off center the drill will follow into the softer material.
    If the car is all OEM, you'll wanna go through it anyways. A re-ring and a standard bearing set is nothing and when yer done no oil leaks... Do the trans front seal while yer in there! ws
    Last edited: Sep 6, 2018
    Electra man likes this.
  15. Electra man

    Electra man Older and Slower

    To be honest the engine only has 61k on it. Compression is excellent and it doesn't burn a drop of oil. Currently the only leak is coming from the oil pressure sensor. I will pull it to reseal and paint next winter but mechanically no complaints. My main concern is that original timing chain cam sprocket. I've only floored the car once since I've had it because that's really worrying me. But I had to have it on the road for this season so I've been lightfooting it. - Bill
  16. gsx455-4ever

    gsx455-4ever Gold Level Contributor

    The passenger side manifold is the one with that 4 inch bolt thru the manifold. I've never had any luck with that one. As long as you are going to lay it up for the winter why not pull the heads and have them gone over at the same time you go after the timing chain . Maybe let the machine shop handle pulling the manifold because they have to machine the manifold and check the head anyway .

    I have also gotten all the other bolts out of the manifold , Cut the head off the 4 inch bolt and worked the manifold back and forth on the head . With MUCH lubricant like Aero Kroil
  17. yachtsmanbill

    yachtsmanbill Well-Known Member

    That shop is gonna charge him an hour to pull that lousy bolt. Heres salt in the wounds for ya E-Man.... ws




  18. Jim Weise

    Jim Weise 1000+HP

    In my profession as a Buick engine builder, I have broken down more cores than I can recall, here is my experience:

    No heat- 90% of all the thru bolts will break, or you will strip the head till it's round- 25% of the blind hole bolts will break- The blind hole bolts almost always break in the manifold, not the head.. as they are rusted to the manifold.

    With Heat (glow casting cherry Red with Ox-Acyt torch) - 25% of the thru bolts will break, 5% of the blind ones will.

    Here is a trick.. heat the casting where the bolt goes into for the thru bolts, or the manifold where the longer blind bolts go thru.. and then rap the head of the bolt sharply several times with a Hammer.. Then pound on a six point socket, and with a 3/8 air gun, sneak up on it a bit, the weaker air gun hammering will help loosen the bolt.

    I have loosened exhaust bolts that we pound a 13mm socket on... it's actually not that uncommon, on the long bolt on the pass side.

    And since your pulling the engine, you will be able to access any bolt that breaks off, to install a heli-coil. So your good.

  19. Electra man

    Electra man Older and Slower

    I only hope I get that lucky Lou! Like I've said me and Murphy don't always get along. I'll be putting the car on the lift by late Nov. early Dec. depending on the weather. At that time I'm going to Kroil those bolts to death and repeat every couple of days while I start on other things. The good thing about the upper bolts is you can juice them from both sides. Those 3 lower bolts will be arrrrh territory.
    Bill your a warm and wonderful human being. I hope to be posting similar pics sometime in December. The suspension was fun, this job on the other hand..well.... Wish me luck boys.
    If the manifold does end up being bad are there replacements available? - Bill
  20. Electra man

    Electra man Older and Slower

    Thanks Jim, words to live by. But I hadn't planned on pulling the engine, only the head if I have to. I'm guessing I'll have to though. - Bill

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