When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
About to put another batch of new bits on the car and would love to get the fan housing looking like it was originally.
Is there a really good way to clean it and renew the finish?
If not, the next effort is to go with factory process and not powdercoat. I am reading in some previous posts that Porsche used an "anodic coating like Dow 17 followed by an organic coating or inorganic sealant".
How does one renew that finish/coating ? Who does work like that?
Pic of new fan and re-plated pulley halves and nut, just as a teaser:
I have had some luck cleaning with a citrus solution and lightly soda blasting the housing, then rubbing it back up with a clean oily cloth. The trick is getting the black to come back out for an original look, the finish is not consistent so can't be replicated with paint or coatings.
The black chromate was supposedly treated with Tectyl (a corrosion preventative made by Valvoline) at the factory. I'm reading that was the process for quite some time and there are some friends that restore the early cars that have dealt with this too. Tectyl seems to be difficult to source in the U.S. now. I'm finding out via some sources that using another "oils" produces good results. The PO of my car, who does lots of restoration projects for himself, likes to use Gibbs Penetrating Oil on such magnesium parts. I had read about people using it on old "hot rods" on the mag wheels to give the nice dark gray patina. I'll try it on this application and report back.
Interestingly, this black chromated magnesium part is a bit of Porsche history.
Sorry thought you had asked about the fan itself. AFAIK you are correct but I don't know what chemical conversion was used. The spec for Dow conversions would be MIL(AMS)-M-3171. I have a copy of both Mil and AMS specs someplace but I don't believe any will result in the same finish. Most will give a gray, green or gold coloring depending on alloy and temper.
Problem is some of these process caused health issues and are no longer used.
You might try contacting Valvoline and see if they have a product that will mimic the black.
I used the Gibbs oil. It looks like Kroil, but smells different and it seems to leave a finish on the parts that is waxy. I think my "freshening project" turned out well.
Looks great. It is amazing how simple things like a fresh sound deadening pad and fresh brightwork will make huge difference how the engine bay will look. I am in the process of having my engine tin all painted. I should have dropped the engine but replaced the pad with the engine in place. Just changing the pad alone was huge.
I used the Gibbs oil. It looks like Kroil, but smells different and it seems to leave an finish on the parts that is waxy. I think my "freshening project" turned out well.
great looking engine bay! that is in my todo list on my car to make the engine sparkle a bit!