aluminum heads - avoiding corrosion

[Kube]

I'd like to know any proven methods you guys may have employed to avoid electrolysis between the aluminum head and (specifically) the studs.

[19Fordy]

I use this stuff.
http://www.no-rosion.com/norosioncoolant.htm

[Brian]

When fitting the heads, I liberally coat each and every stud with nickle based anti-seize compound. This, after fitting each stud into the block with sealer to prevent coolant weeping up the threads. I also use 50/50 mix of Prestone and water, and make up sacrificial zinc anodes which can be fitted into each head in same manner as the temp probes. Additionally...I run one of those rubber earthing straps from under engine onto the ground. [ I have a daughter that always got a 'static' shock from the car- fitting said earthing strap prevents that, and may also aid in preventing electrolysis of heads?- dunno, don't hurt none!]

I know the above statement sounds like I'm overdoing it; probably am, however, taking the appropriate steps when fitting [using antiseize compound on studs], and running a good anti-corrosion substance in the coolant are the most important steps. Doing so will enable one to remove those heads years later.

[Kube]

Thanks for the responses guys. While I understand the chemicals the cooling system should be filled with as well as the need for composite gaskets I am still not certain of a good "fix" for around the studs.
It occurred to me to utilize an anti-seize type product on each stud but will that prevent the transfer of electrical current between the steel studs and the aluminum heads?

[Brian]

It occurred to me to utilize an anti-seize type product on each stud but will that prevent the transfer of electrical current between the steel studs and the aluminum heads

Doesn't appear to have any detrimetal effects; the only electrical current that needs to transfer through to the studs is the voltage from the plugs. More importantly, the antiseize precludes the formation of that white corrosion in the stud holes which, ultimately will weld the studs into the holes.

[Fordors]

Sponsored Links (Register now to hide all advertisements)

Kube, I have a can of anti-seize that is mica based and in a FB thread some time ago I learned that it is a non-conductor. Mine is old, I got it from my brother in law long ago but I'm sure it must be readily available.

[4t8v8]

I wrapped the bolts with Teflon tape 25 years ago. Used 2 wraps on each bolt. Easy and no mess involved. Had to pull the heads last winter and had 0 corrosion. Worked great.

[V8COOPMAN]

Not sure that what you're hoping for is reasonably feasible when you take into consideration the fact that the stud nut is going to end-up electrically bonded to the stud via the amazing clamping forces achieved through direct thread interaction, as well as the similar clamping forces imposed on the bare, aluminum head, even via the use of a metal washer. That's why things like a dielectric union usually depend on a non-conducting insulator to separate the dis-similar metals successfully. As usual though, I could be full of it. Maybe someone else has a more-intelligent answer. DD

[AnthonyG]

like on out boards and stern drive boats there are sacrificial zinc anodes that can be purchased and put in the cooling system ( usually the engine coolant intake ) and grounded to mitigate the galvanic corrosion. They need o checked periodically and replaced when depleated.

[Chris Nelson]

In 20 some years, I have not had any problem with corrosion on the studs. I use Permatex #2 on the threads into the block and water wont come up the thread. Teflon may create a problem since you need a good ground or your plugs wont fire. If you use copper gaskets, that is not a problem, but composite gaskets with Teflon tape on the threads may create a poor ground and we all know from previous threads how important good grounds are.

[47Merc]

I have thought about this for a while and the next time I pull my engine down I intend to clean up the studs very well and then put shrink tube over them before the heads go on. Maybe even put some anti-seize over the shrink tube.

As far as Chris's comments above go, I would have thought that the connection between the studs, nuts and washers would have been more than enough for a good ground.

[Ross F-1]

Try using "G-O5" type antifreeze. It is a type of antifreeze, like DexCool, not a brand name. It is what is spec'd by Mercedes, SAAB, and other european cars that may have dissimilar metals. Specifically, it was developed for aluminum engines that have steel seal rings in the head gaskets. It costs very little more than the green stuff. NAPA and Wally World carry it. You need to flush the old stuff out if changing to it.

[cmbrucew]

Mike
Would a copper strap from the aluminum head to ground eliminate the problem?
Bruce

[36tudordeluxe]

Originally Posted by cmbrucew

Mike
Would a copper strap from the aluminum head to ground eliminate the problem?
Bruce

Like to hear the answer to that!

[Brian]

What problem?

[scooder]

Copper head gaskets are fine for use in an aluminium head iron block combination. I know the science says it's a bad idea, but the real world is different, the parts clamped ie head face where it is clamped to the gasket/block doesn't corrode. The corrosion happens when the head face is open to the water, with no gasket cover.
So I cant see the problem here, coating the studs with some kind of anti seize works well, anode in the cooling system is also proven to work if you look into outboard motors made from a mix of metals running in a salt laden environment.
Martin.

[PeterC]

Re "sacrificial zinc anodes" and reference to use on boat drives ... my concern would be what becomes of the sacrificial materials that slough off from the electrolysis decay on a closed cooling system?? On a boat it just dissipates into the surrounding sea - but in a closed hot engine block and radiator ... does it adhere to the cast or copper surfaces or just circulate?

[jimTN]

Here is what I use and it seems to have worked over the years in my Model T's.
http://www.modeltford.com/item/3001AHS.aspx

[Kube]

Thanks guys for all the advice.
I have come to realize I am perhaps worrying a bit too much about this.
I had thought of the heat shrink tube over the studs and may use that in part.
Of course a high quality coolant / corrosion inhibitor is also a requisite.
I was planning on placing a thin fiber washer between each washer and the head as well.

[sidevalve8ba]

How and where would you put one of these sacrificial anodes in an 8ba? It seems to me that the piece of wire could become weak over time.