Rusted bolt holes

[Lead_Foot]

Not sure if this the right place to start, but need to start somewhere.

 

I have an old flathead that I've removed the heads. Some of the bolts where rusted and I am sure that the bolt holes/threads are rusted (several were wet with water). I've cleaned up the bolts. I will wire brush the holes and I hit with PB Blaster, but I am asking if there is a more long term solution to treat the holes/threads. Is some type of paint or phosphoric acid product possible? Since these are in the engine block they'll get hot.

 

Thanks for any comments.

[m-mman]

Anytime you work with old threaded items (bolts and holes) you are wise to clean them as you describe BUT also chase them with a good tap & die.

You are not cutting new threads, but you will be surprised how much crud is removed and a tap/die will also straighten the mangled threads. 

 

Lubricate the threads during reassembly, but once a bolt is properly installed into a hole the hole is sealed and it does its job of holding things together. They aren't supposed to leak. Heat?Cold? yeah but that's what bolts do.  The only real issue is with exhaust manifold bolts. These things get real hot and there is little you can do to prevent rusting and eventually getting stuck.

 

There does exist something called "anti-seize compound" which has a very high melting  point and can aid in future bolt removal but exhaust bolts are typically always a pain to remove no mater what you do. 

[Spinneyhill]

That chasing tap and die nut are just that, not the usual thread cutting types.

[Mike "Hubbie" Stearns]

M-mman, I do agree that chasing the threads is a big part as well in lubing when reassembling. I personally use anti seize on all exhaust nuts and bolts. Anti seize is a high heat lubercant.  It's best to use when you have steel bolt installed in aluminum. Dissimilar metals will have electrolysis as well. Anytime stainless steel nuts and bolts are assembled should have a anti seize used as they will guald and won't come apart without cutting. 

As for a bolt being sealed when installed is incorrect. Straight threaded items will require a thread sealant ( pipe dope ) or a mechanism seal. That's why mechanics always dip head bolts in sealant when installing on older sub chevy engines due to the bolts going into the water jacket. Pipe threads are tapered and create a somewhat of a seal, but still need to have a thread sealant used. The plumbing company I work for require the use of both tape and dope on all threaded joints. 

[PFitz]

Yes, threads have to have a small amount of clearance or they will be too tight to  thread together. When tightened, that clearance all gets forced to one side of the teeth and can cause a path for leakage - even with tapered pipe threads.  That's why they need to be sealed  in applications where the bolt hole extends into an area where oil or water need to be retained.

 

Paul

Edited November 29, 2018 by PFitz (see edit history)

[JACK M]

NAPA sells a small can of gasket sealer.

It is similar to the old Indian Head sealer but not as thick.

Either one of those will seal threads.

Required in marine engines so that you may get stuff apart later.

Works good on o-ring seals as well.

[Lead_Foot]

Thanks everyone for your comments. My concern is about the bolt hole. This is my first time to breakdown a flathead chasing a pesky gas leak into the cooling system. I can see that the original V8 design is such that some of the head bolts and holes are exposed to the cooling water in both the head and block. On inspection the bolts are rusted and pitted, but they can either be cleaned up or replaced. My original question (perhaps not well worded) is about the threaded portion of the hole in the block. I will clean the threads and squirt some lubricant on them. I am asking about a more long-term prevention to further deterioration of the threads and bolt hole. Is there anything that penetrates the metal to prevent this without softening the threads?

 

Perhaps I am over thinking this. My dad & I restored this 49 F1. I'm getting old and I plan to pass on to others in the family, so I am thinking long term.

 

Thanks again.

Edited November 30, 2018 by Lead_Foot (see edit history)

[chistech]

If your worried about the holes exposed in the water jacket area, they will not continue to deteriorate much if any when they’re wet and if you use distilled water only with antifreeze. Don’t use tap water or even bottled water, only distilled. All rusting in the cooling system will stop.

   As far as the bolts go, I try and replace any with any sort of deterioration and especially head bolts. My own 32’ Olds is a flat head and exactly as you described as far as the bolts exposed to the cooling jacket. I found a guy in NH that made a ton of high head head bolts years ago and sells them now on eBay. 

Edited November 30, 2018 by chistech (see edit history)

[Frank DuVal]

Not sure why rusting will stop with the use of distilled water, but using distilled is a GREAT idea. 

 

Hmm, Google says, seems it might have to do with no free oxygen in distilled water. So, as long as the cooling system is completely full of distilled water, maybe. But, our old systems have an air space above the water line in the radiator, so there is free oxygen for the water to circulate (water pump) through the heads/block.

 

Anyway I am suggesting a rethreading tap and die set company, Jawco. I use their rethreading products both at work and in my hobby.

 

http://handtools.jawco.com/viewitems/all-categories/rethreading-tap-die-file-sets-2?&plpver=10

[Spinneyhill]

Yes. It will work for a while. But there is turbulence in the radiator from returning coolant so air (oxygen) will be introduced.

[Rusty_OToole]

If the holes are badly corroded and you are afraid of thread stripping you could put in a threaded insert. Otherwise use sealant as described above, and keep good antifreeze in the system and it won't corrode. The antifreeze you get today is much better than the old stuff and keeps off corrosion even in aluminum engines.

 

There are other types of coolant that prevent corrosion if you live in a hot part of the country where antifreeze is not required. Jay Leno swears by Evans Coolant. https://www.evanscoolant.com/