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As I'm rebuilding my flathead, should I replace the manifold studs?  I bought a stud/nut/washer kit from Vintage Power Wagons.  It has new studs, new cone-shaped washers and nuts.  I really bought it for the washers and nuts, as the ones previously on the engine were not correct (and the manifold is cracked presumably as a result of this).

 

One or two of the studs have seen better days, so I might replace those anyway, but the rest look pretty good.  However, I wonder if I should replace them all to give myself better insurance against coolant leakage around the studs.  I think some or all of them go into the coolant jacket, don't they?  This engine came out of another vehicle, so I don't know if it leaked around the studs or not, although I don't remember there being any evidence of it as I disassembled it. 

 

If I'm going to replace any or all of the studs, now is the time to do it, but I foresee it being painful.  Removing studs always seems that way, with lots of potential to break them off.  If replacement is recommended, I'd appreciate some tips on removing the old studs and tips on installing the new ones, especially the type of sealant to use, considering this is an area that sees a lot of heat, with the exhaust being right there.

 

Thanks,

 

Matt

Edited by Matt Wilson

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I think you  already know what the best would be ... You don`t know the history of the engine, not sure if the studs which goes into the water jacket (not all) are leaking or not, you already have a complete set of new studs.

Since this seems to be a rebuild, not a repair, the engine is out anyway. Best chance to get to the bolts (and other parts).

You also mentioned that the manifold was cracked presumable due to improper bolting, so it is possible one or more have been over-stressed.

Do yourself a favor and replace them all.  You would bite yourself in the butt, if a stud breaks while final assembly and eventually already installed in the vehicle ...

 

How to get them safely out ? I would several times apply a good penetrating oil where the studs are bolted to the block. Then put on two nuts to the stud(s) and counter them to each other. Apply a good amount of heat to the area of the block where the studs are located (heat gun, torch, ..). Take a wrench and carefully try to loosen it. Sometimes it is necessary to apply heat and let it cool down several times. If one should break, it is not nice but not a dooms day. (Let`s talk about it when it should happen). Good thing would then be, you know that it was time to replace that stud ... ;)

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A good stud removal tool/dies set will generally remove most any studs.... but if the studs look good I won't replace them just because...chances of them leaking are greater after new  sealed installs IMO.

Stud installer tool SO.JPG

Stud Remover Snap On (3).JPG

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26 minutes ago, Matt Wilson said:

Thanks for responses, guys.  I think I will try my hand at replacing the one or two worst-looking studs and see how that goes, and then I'll go from there.

 

make sure to get some penetrating oil on them for a while first and maybe some heat so you don't snap them off.

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19 minutes ago, ggdad1951 said:

 

make sure to get some penetrating oil on them for a while first and maybe some heat so you don't snap them off.

Thanks, I will certainly do that.

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I would say that if a stud can not be unscrewed, then it is not going to be leaking coolant.  If threads are good, I would leave well enough alone.  Each stud should be examined with this thought in mind.  Just my humble opinion!

Dennnis M. in W. Tenn.

 

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Yeah breaking studs is my least favorite. I would run a die over the existing studs before trying to pull them. Of course if they wanna come out or are wiggling then that’s different.

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13 hours ago, Radarsonwheels said:

Yeah breaking studs is my least favorite. I would run a die over the existing studs before trying to pull them. Of course if they wanna come out or are wiggling then that’s different.

Yeah, I have a thread chaser I can use on them and maybe I'll leave them.  I guess I was mainly trying to get a feel for people's experiences with leaving the existing studs and then having them leak later on.  I figured now would be the time to replace them if leaving them would pose a significant risk of leakage.  But I also don't want to have issues with studs breaking, etc.

Edited by Matt Wilson

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Ok, not trying to decide, if it is better just to swap those which are obviously no longer good or replace them all.

It is fairly difficult to evaluate the condition of the bolts, not being in front of them.

My comment in #2 is just what I would feel good about myself. I hate to do things twice (and I did ...).

Regarding the risk of leaking studs: If you thoroughly clean the threads and apply a good sealer (I used one for higher temperature) to them there shouldn`t appear a leakage problem. At least I had zero problems on that.

Good luck ! Jan

 

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8 hours ago, PT81Jan said:

Ok, not trying to decide, if it is better just to swap those which are obviously no longer good or replace them all.

It is fairly difficult to evaluate the condition of the bolts, not being in front of them.

My comment in #2 is just what I would feel good about myself. I hate to do things twice (and I did ...).

Regarding the risk of leaking studs: If you thoroughly clean the threads and apply a good sealer (I used one for higher temperature) to them there shouldn`t appear a leakage problem. At least I had zero problems on that.

Good luck ! Jan

 

Thanks, Jan.  Believe me, I know about doing things twice, and I hate it.  When you mentioned not having problems with leaking studs, are you talking about studs you've installed?  I'm talking about having leaks with studs that I haven't replaced.  Not sure if leaving the original studs is a known problem area for these engines, in terms of leakage.

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12 hours ago, Matt Wilson said:

Thanks, Jan.  Believe me, I know about doing things twice, and I hate it.  When you mentioned not having problems with leaking studs, are you talking about studs you've installed?  I'm talking about having leaks with studs that I haven't replaced.  Not sure if leaving the original studs is a known problem area for these engines, in terms of leakage.

 

I swapped all the manifold studs on my engine, and yes I did install them myself. I can´exactly remember how many of them are breaking through into the water jacket. Maybe 2 or 3 (?)

But this easily can be seen when the specific stud is out. I don`t know, if leakage at that bolts is a common problem. Never had a leak there since the rebuild 5 years ago and regularly use.

Good preparation and the right stuff is the basic for success in my opinion.

Ah, and I think it is more difficult to get an installed + leaking stud leak-free.

But again, ask 5 people, get 5 answers ...;) Just my experience ...

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May or may not be pertinent but you will have to re torque all these after a few heating cycles on the manifolds. To me this is a more significant issue with these studs. Not leaks. It is a pretty easy job if the manifolds are off. Rather do it then than to have one break or strip later.

Jeff

 

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I'm with Jan on this... You have the engine out where it's easy to work on, and you have all new studs. Now's the time...

I believe most of the studs end up into the coolant. Just play it safe and put a good quality thread sealant on all of them. I have used a PTFE pipe thread sealant and it has worked fine. I know there are some high temp versions out there, Permetex makes one, that may be more conducive to exhaust studs. But I've had success with the normal stuff. I also like the Permetex #9 Tack and Seal for stuff like that.

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Thanks, guys.  Hmmmm.....more food for thought.  Most of the studs are in really good visual condition, with very little rust.  It's only a couple that have significant rust, but even those don't look terrible.  Anyway, I'll be thinking about what you guys said.  Much appreciated.

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engine easily accessible...studs ripe for replacement...WHY NOT swap 'em out.  WAY easier now than later.  All this fear of new ones leaking is bunk, replace 'em properly and be assured they won't snap off when it'll be HARD to replace 'em w/o a bunch of work.

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3 hours ago, ggdad1951 said:

engine easily accessible...studs ripe for replacement...WHY NOT swap 'em out.  WAY easier now than later.  All this fear of new ones leaking is bunk, replace 'em properly and be assured they won't snap off when it'll be HARD to replace 'em w/o a bunch of work.

I'm not particularly worried about new ones leaking.  I'm more concerned about old ones leaking if I don't replace them.  As for snapping off later, most of them look almost new, so I doubt that's an issue on those, but a couple look a little worse, so could be an issue for those.  I just don't want to break any off while I'm replacing them when it might not even be necessary to replace them.  That would make a bunch of work for sure.  I appreciate all the replies.  Still pondering....  Maybe I'll have time to look at it this weekend.

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I have revived a few of these motors and the worst one, was the block that didn't have coolant in it for years......

here is my "redneck" stud removal on the left side. :)

(right side I had to tap out... block still in the truck)

studs.JPG.b1780c7222a08d74af16610320a2dac1.JPG

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I am on the side of replacing manifold studs and bolts as a set during a full engine rebuild...I've seen these corroded where there is pitting along the shanks, even though they were still useable...since exhaust fasteners see the most heat, any significant corrosion can lead to failure from yielding or fracturing, which is not good for manifold sealing.  I have replaced individual studs and bolts on engine repairs, as inspection of stud and bolt surfaces showed no pitting or obvious signs of stretching, and those repairs lasted for over 10 years.  In either case, the new studs and bolts were almost as rusty looking after several years of use as the originals, so it was hard to tell at a glance which were new and which were vintage :cool:

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I am a fan of replacing easy stuff while it is easy to replace. 

 

Stud removal is easiest with heat and penetrating oil.  For the items that I am replacing I will always soak for 2 or 3 days then MIG weld a blob on the shaft surface.  It does nothing more than throw a lot of heat in a short amount of time.  I have a stud remover like Don showed above and the studs usually come right out.

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Ok, I think I'm starting to get convinced to at least try replacing those couple of corroded studs.  Depending on how those go, I my tey my hand at the others.  Good idea on the welding.  I have a welder.  I've also heard of a technique whereby you heat up the area around the stud and hold a candle or other wax item up to the base of the stud and if you have heated the area enough, but not too much, the wax will wick into the microscopic gaps between the stud and the parent part (in this case the block). The wax provides lubrication to allow the stud to come out when no other technique will work.  Some guys swear by this technique.  It's also reported to work for removing other types of corroded threaded fasteners.

Edited by Matt Wilson

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don't over think it Matt, you'll get them out. Patience and penetrating oil. :) don't force them if they bind, let the stud cool and come back at it.

I spent three days last year removing a water pump, one bolt 1/8" at a time (the block and radiator still in the truck)

i'll bet you either get them out no problem..... FYI, I bought my replacement studs at Napa

I'd only use the welding as the last resort. :)

 

good luck 

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