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Thread: Removal of Intake and Exhaust manifold. Austin Healey BJ7

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    Removal of Intake and Exhaust manifold. Austin Healey BJ7

    The first time I have attempted to remove the Intake and/or Exhaust manifold on my BJ7.
    The only reason I am trying to remove is I wanted to install my Moss exhaust but the down pipe connection to the exhaust manifold I canít break free. Tried everything, PB Blaster, Seafoam, 50/50 Acetone and ATF and lastly heat but it was so difficult to get to I decided to try and remove the manifold.
    I have freed the nuts on the Intake manifold (read it is better to remove it also) but canít get the manifold to break loose. Being new to this I am worried I will crack or break something. Any guidance on next steps would be appreciated. I will attach photos of my progress and the exhaust I am trying to break loose from the Exhaust manifold.
    Thank you for any help. FYI I am rebuilding carbs and that kind of started the whole mess.
    Bryan
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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Hi Bryan,
    In your first picture look at the front carb area - there is a vertical bolt head just to the rear of the carb mounting flange and just towards the head there are two vertical bolt heads going down thru a bracket (possibly throttle linkage?). Now look at the rear carb area and see the same three corresponding bolts..... These all go down thru the intake manifold into the exhaust manifolds. You will need to remove those six bolts to separate the intake from the exhaust. Then remove the intake first, and then you can free the exhaust. Moss catalogue has a pretty good exploded view showing the bolts.

    As to getting them loose, you may need to tap the manifolds with a soft mallet or sometimes drive a screwdriver into the gap where the manifolds meet the head - but be very careful/gentile if a gasket surface is affected.

    Good luck.
    Dave

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Dave, Thank you. I was not sure how they were connected. Is it best to go ahead and remove both Intakes and put on a new gasket?
    Bryan

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Bryan,
    Tough question - you never know what kind of hornets nest you may find when exploring new territory.

    If I was going to remove them, I think I would probably separate them. However, the first test I would do is try loosening the 6 bolts - I think they go into tapped holes in the exhaust manifold but
    may go thru and have nuts on the bottom.
    Either way they may be rusted too so they might be difficult too. I've got headers and it's been awhile since I've had the stock ones apart.

    There can also be areal argument for doing all the exhaust system at once and be done with it. It should be maintenance free for a long time and
    you know the condition of all of it.


    What ever you end up doing, do yourself or some future owner a real favor and generously apply anti-seize when you put things back together, someone will surely thank you .

    Dave

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    An impact gun and socket will probably help get the bolts out.

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Thank you both. I was able to remove the nuts from the studs so hopefully no issues with the bolts through the Intake into the Exhaust manifold. I will be generous with the anti-sieze for sure. I actually found one stud with no nut or washer at the bottom of the intake. So might be a good idea to take both off and evaluate.
    Bryan

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Quote Originally Posted by BLong63AH View Post
    Thank you both. I was able to remove the nuts from the studs so hopefully no issues with the bolts through the Intake into the Exhaust manifold. I will be generous with the anti-sieze for sure. I actually found one stud with no nut or washer at the bottom of the intake. So might be a good idea to take both off and evaluate.
    Bryan
    Be careful removing the vertical bolts that connect the intake and exhaust manifolds. It's possible to break them off in the blind hole. Go slow, use a lot of penetrant, and when they move turn them out a bit, then turn them back. Work them out gradually until they turn freely. Use anti-seize when reinstalling them.
    Steve Byers
    HBJ8L/36666
    BJ8 Registry
    Havelock, NC

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    will do.Thank you Steve

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Thank you to everyone for their advice. I was able to remove both Intake and exhaust manifolds. Does anyone know the original color of the exhaust manifold. I would like to go ahead and paint if necessary while I have everything off.
    Thank you again,
    Bryan

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Quote Originally Posted by BLong63AH View Post
    Thank you to everyone for their advice. I was able to remove both Intake and exhaust manifolds. Does anyone know the original color of the exhaust manifold. I would like to go ahead and paint if necessary while I have everything off.
    Thank you again,
    Bryan
    Bryan, whatever you use to paint the exhaust manifolds is not going to last very long anyway due to the high heat. Some people have used barbecue grill paint. For long-term durability, I have found the Jet-Hot coating to be the thing to use. Twenty-one years and 90,500 miles after having my exhaust manifolds Jet Hot coated (aluminum color), they are pretty much unchanged except for some minor traces of rusting on the sharp corners. The cost in 1998 was $185.
    www.jet-hot.com
    Steve Byers
    HBJ8L/36666
    BJ8 Registry
    Havelock, NC

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    Steve,
    Thank you. I have been looking into Jet-Hot and I believe there is a location in Oklahoma City (about an hour and a half) that does it. I will check with them on cost.
    Have a great weekend!
    Bryan

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    Re: Removal of Intake and Exhaust manifold. Austin Healey BJ7

    I had my BJ8's exhaust manifold Jet-Hot coated three years ago; the cost was around $400 (I got mine in a dark grey). I believe the company went through bankruptcy a few years ago and may be under new ownership. Service was acceptable. I had hoped the coating would eliminate the warm-start problem caused by fuel vaporization, but the improvement was negligible if at all (but I didn't get 'before and after' temperature readings with an IR sensor).

    There are other coatings providers; I can't vouch for them but suspect the result is similar to Jet-Hot (it ain't rocket science, and I think the process is similar to powder coating). There was one in southern California that, IIRC, was featured on 'Wheeler Dealers,' and you might be able to save some money if you shop around. I used high-temp paint on my BN2's manifold, and it has held up for the few hundred miles I've put on it.

    Edit: A quick google search produced at least one alternative (Jet-Hot came out on top of the search, so they're internet marketing-savvy; some of your cost probably goes to that):

    https://boneheadperformance.com/high...ance-coatings/

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