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Discussion Starter · #1 ·
I don't want to pay $6/bolt for the valve cover studs for the composite valve covers, so a forum vendor is investigating offering these in aluminum at a significantly reduced price. While thinking about potential down side to this endeavor, I began to wonder about the likelihood of galvanic corrosion of the aluminum studs due to being bolted to the nifty polished stainless valve cover bolts i am purchasing.

The proper anti-seize compound would inhibit such corrosion, but I don't know how healthy it would be for stray anti-seize to be floating around through the oil to the bearings. It may be better to forego the anti-seize and simply replace the stud if corrosion is excessive.

Any INFORMED opinions out there; other than I am being too paranoid?
 

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Galvanic corrosion occurs when two dissimlar metals are present, and there is an electrical current/path present to allow the flow of electrons between the anode and cathode.

I don't forsee you using the valve cover bolts as a grounding point, so I'm pretty sure you'll be fine on the corrosion aspect. The stainless steel threads will gaul (seize) onto the aluminum studs if you do not use an antiseize compound or you can have the aluminum studs anodized. I'm quite sure a small amount of antisieze compound will be just fine or thread seal paste, not tape.
 

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Discussion Starter · #3 ·
Thanks for responding Rollin.

Your thoughts about the lack of a continuous electrical circuit are valid. I imagine such a circuit would definitely accelerate the corrosion. I suppose the insulating effect of the "plastic" valve covers will also help in this regard. I believe a galvanic reaction will still occur, albeit on a lesser scale, due to the mere contact of two dissimilar metals so far separated on the noble scale. However, the composite VC on one side of the "circuit" and application of a dielectric antiseize between the stud and bolt and between stud and head could nip it in the bud.

I will talk to the Loc-Tite tech people about the risks of anti-sieze in the bearings. I will also look into the anodizing angle.
 

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http://corrosion-doctors.org/Definitions/galvanic-series.htm

Scroll down to Galvanic Compatibility. Aluminum to stainless is less than .50, but I don't know if high temperature and low humidity qualifies as a normal environment.

My first car had magnesium alloy wheels with steel lug nuts. I guess the first owners had never taken the wheels off, because road salt had electro-welded them to the car. When I first took the wheels off, I had to put a ten foot pipe on the lug wrench and stand on it.

I would still use antiseize to prevent galling and to reduce the chance of corrosion.
 
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