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How to remove the phosphate coating from cam lobes

I want to remove the zinc phosphate layer formed on the cam lobes (made of chilled cast iron) by lubricants. I'm scared that if I remove the Zinc phosphate using acid, KOH or other type of cleaner, it may cause wear on the surface and may change the surface roughness of cam lobe. Is there any cleaner that can remove the zinc phosphate layer from the surface of cam lobes without affecting the cam surface?

Haque, Taba
Leeds University, UK - Leeds, West Yorkshire, UK
2005

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Hi Taba. We might similarly ask if there any de-icer that can eliminate the ice on a skating pond without affecting the quality of the skating :-)

Sure, you can remove the phosphatizing without affecting the steel ... but not without adversely affecting the operation of the cam. The smooth operation of the cam relies upon the oil retention qualities, the smoothing effects, and the dry lubrication capacity of the phosphate coating. A plain steel cam without a phosphate coating will not work nearly as well.

The phosphatizing is not formed by lubricants during operation, it is applied by the factory, and is intended to prevent galling during the break-in period and the first split-second after long periods of idleness where there may not be adequate lubrication, and to keep the component steeped in oil to prevent corrosion. It may be manganese phosphating rather than zinc phosphating. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005





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