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Cadmium for use in internal engine parts

I am in the hobby of automotive restoration, specifically older Porsches. The model 356 originally utilized Cadmium plating for corrosion protection of steel linkages, clamps, fasteners, etc. I choose to restore these engines using the original cadmium plating instead of the silver zinc because of its originality, and because fewer and fewer cars are being returned to their original state. I believe this current trend is creating a vaccuum of knowlege of how/why the manufacturer chose a certain direction. Here is my question: the valve covers on the 356 engine were Cadmuim plated on the exterior for sure, but because the Cadmium plating process is not selective, is it possible that the Cadmium on the internal engine side of the valve cover can create an issue with bearing wear due to the sacrificial nature of cadmium? It has to go somewhere. I am wondering if maybe the factory removed the cadmium on the inside of the valve cover due to the concern of particles entering the bearings.

Tom McCoy
Hobbyist, Engineer - Atlanta, Georgia
July 22, 2009

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First of two simultaneous responses --

If they had any problem with it, they would have masked the inside. Cad is sometimes used as a bearing material, so I doubt if cad dust would be a problem. Peeling cad would be a problem.

James Watts
- Navarre, Florida
July 24, 2009

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Second of two simultaneous responses --

Most likely there was only a little cadmium deposited on the inside of the valve covers. Certainly no one cared how much cadmium there was inside, since engine oil would prevent any significant corrosion, and a tiny bit of cadmium, if it did dissolve in oil, would have no affect on anything.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
July 24, 2009