Conference vicki::boats

I haven't worked on inboard boat engines, but have done considerable work on
cars, construction equipment, and aircraft engines.  I would definitely soak
the nuts/bolts overnight in some good penetrating oil.  I cannot recommend a
particular brand since there are so many new ones on the market.  Go to the
local automotive store and ask their recommendation (maybe someone in this file
can recomend one).

Use a six point socket and enough leverage.  A smooth pull with a breaker bar
or pipe extension is much better than a jerky one on a rachet.

If necessary apply heat -- BE CAREFUL of gas fumes.

When you put it back together use neversieze or some such product, the next time
it will come apart a lot easier.  I use an anti-sieze compound on everything I
take apart and it works well for me.  I have been able to reuse exhaust "U" 
clamps because they were treated with the stuff.

If you happen to break off a stud.  Square it off, center punch it and drill
it out a little at a time.  When you get to the threads you can either twist
out the remaining threads with needle nose pliers or run a tap down to clean
up the threads.

Good Luck

The days are already getting longer - won't be long now

Gordon

    
    
      For penetrating oil try a product called THRUST, it foam like heck
    when you spray it on, and it works excellent. and if this is a job you
    are gonna do over the weekend spray them every day so the oil has a
    chance to really penetrate into the threads.
    
      I too would recomend the heating technique, but as stated in the
    laast reply be carefull !  and also when you reinstall the manifold 
    definatly use the neversieze compound, that stuff is great.
    
                                                   Lee
    

    I just did 2 sets of manifolds this past season. None of the bolts
    were seized. My manifolds had a combination of bolts and studs
    with nuts.  The only problem was that the nuts were badly rusted,
    so we chiseled them off. As for the never-seize, i certainly agree.
    
    As for the Muriatic acid, i don't see a problem, its common 
    knowledge, should be fine.
    
    I would also recommed a new gasket set for the manifolds.
    
    
    Its time consuming, to be patient.
    
    JIm.

I did my manifolds a couple of years ago because of the same problem.  I pulled
them off and had the local shop dip them for me.  I'm not sure what they used
but I'm sure it was some type of acid.  The end result was a relatively clean
although still rusty manifold.  Remember the process also removes the exterior
paint so you'll have to repaint them.  Also I agree that you should replace the
gaskets before you reinstall them.

My two cents,
"Harpoonist"

    I'm gearing up for the job. I sprayed the nuts with penetrating oil
    last sat. I will give them another shot soon and then the 1st moderate
    day I will take a crack at loosening the nuts. Thanks for the advice.
    
    Bruce

    Bruce, if it seems like it is taking too much force to break the nut
    free to the point that you may snap off the stud instead, you may want
    to try a little trick I used to remove the carb studs from my manifold
    so I could install a carb spacer.  It was obvious that after 27 years,
    the steel studs had "welded" themselves to the aluminum manifold and 
    any further torque was going to snap them off and leave me with the
    original manifold pretty useless.  I put a second same size nut onto
    the stud and by using two wrenches I snugged them together very
    tightly.  I also aligned the sides of the nuts.  I then put a deep well
    socket over both nuts and the whole set-up, stud and all came right
    out.  If your studs are really rusty, you may be able to use this
    technique to get them out without having to use an "Easy-out" (which
    is never an easy out) on them.  Jim B. had recommended a foaming
    penetrating oil (which I can't remember the name) that he got in
    Marlboro.  It's worked GREAT on everything that I've used it on
    including some very corroded battery cable bolts which usually just
    snap right off after years of electrolysis action.
    Wayne

    
    The products name is "Break Away", i got it a CAP in Marlboro.
    
    As Wayne has already said, it works, and if my memory is correct
    
    a spray can costs either $2.99 or $3.99
    
    JIm

    Wayne.  I understand that your double nut trick works, but WHY?  What
    does having two nuts on the unchanged size stud have to do with the
    stud not breaking?  You increased the surface area you are torqing
    on but not the stud size which is the part taking the brunt of the
    strain, especially where it goes into the manifold where the nuts
    AREN'T.
    
    Jeff

    Jeff,  I guess I don't know why it would make a difference.  I just
    know it has worked for me in the past.  In this case, I would just as
    soon take out the whole stud and replace it even if it was only
    slightly rusted/corroded.  I suppose that there is a "stud remover
    tool" made but most people just grab a pair of vise grips and destroy
    the stud while hoping it comes out.
    Wayne  

    
    My OMC 5.7l has BRASS nuts on the studs on the exhaust manifold- theyu
    come right off. They are also readily available in one of those red
    HELP blisterpacks. The studs are available also.
    
     If you have steel nuts and they are badly rusted , I would suggest
    that you invest in a "nutcracker" tool that splits the nut. That plus a
    litlle WD40 (or other stuff) should get the nut off without wringing
    off the stud. 
    
     Once the manifold is off, chase the threads on the studs, aplly
    anti-seize, and use brass nuts (do not use SS- they will seize real
    good!) the brass is very soft and thus deforms whenever it hits a rusty
    area.
    
    Dick
    

    
    Don't use Brass or any soft metals on maniflods, you won't be able
    to meet the torque specs.  Use steel, or stainless steel, stainless
    steel will come out later if you need to pull the manifolds.
    
    JIm

Back to my aircraft mechanic days.  The  Continental aircraft engines used brass
nuts and I had the most difficulty removing these.  Most of the time they would
come part way out then bind and the whole stud would come out with it. 
Maybe it had something to do with the high heat generated by aircraft aircooled
engines.

The othe engines used stainless and would come off much easier.

Use what the manufacturer says and use NEVERSIEZE and you shouldn't have any
problems

Gordon

One minor point: most torque specifications are for clean, dry threads. 
When using Neverseize (or something similar) you need to reduce the 
tightening torque somewhat (where somewhat is an unknown amount) to 
avoid overtightening. 

    
      The last time I did manifold work I replaced the studs and the nuts
    with stainless ones. Problem solved. Use neverseize and they come off
    in 4 years like they were put on yesterday.
    
    Alan - Many times tightening torques are for oiled threads. It can of
    course be done either way. The best way to find out is to get the
    specs from the factory book and see what they want.
    
    				Kenny

    While we're on the subject, torque them initially to the factory specs,
    thats if you can find them.  I used 35 lbs. then come back later
    (say 2-4 hrs running time) and re-torque them.
    
    On the gaskets, if you can get individual vs. the one-piece
    your better off, they fit better.
    
    JIm.

    
    Are your nuts brass or bronze?
    
    Fred
    

    In my previous life as an auto mechanic (many moons ago) we 
    routinely used brass nuts (or maybe bronze, whatever, they were
    gold in color) on the exhaust pipes where the front pipe flange
    connects to the manifold.  This spot is very prone to extreme
    heat and rust. We never had a problem with the nuts splitting or 
    cracking even though we socked 'em down with an air wrench, and 
    the brass nuts were always easier to remove next time. In fact,
    we always breathed a sigh of relief if we saw brass flange nuts 
    on a system we had to remove.
    
    I think the key is to use brass nuts that are specifically designed
    for exhaust work. If I remember right, the ones we used were thicker,
    and used an oversized hex head when compared to a similar thread size
    nut made of steel.
    
    Rick

    
    
    The brass nuts I used on the manifolds on myOMC 350 were GM. The nuts are
    signifigantly longer (more holding area) and slighly larger than the
    std steel nuts. I agree with the note earlier that a brass nut of the
    same legth has less holding power and will deform/strip much quicker
    than steel, but that ability is waht allows you to get the nuts off.
    
     I'd much rather have a stripped brass nut than a stud broken off.
    
     If you use SS, make sure you use a good hard, High strength
    stainless. I have snapped off lots soft SS bolts on outboards.
    I have an old Bearcat at hon=me that uses hardened SS Bolts-those are
    really tough and high strangth- also expensive.