Reply With QuoteI removed most of mine. Then I painted it black.
Super Moderator
Cosmoline, the yellow stuff on your engine
discussed that yesterday with a friend and he removed it all with a small soft metal brush in many hours. If you take a too strong brush, too much of the aluminium will come off. Some polish it, others say the keep it as it was done to protect the aluminium.
I have kept it on my grey 750 for 11 years, but influenced by my friend I started now on my Highline and polished for one day already with the intakes out. I also will remove the valve covers and either polish them or repaint them. Now it is the right time to do it when the intakes are out of the engine.
So, what are you doing?
Or how did you do it?
Just left it as is?
I talked with a chemical technician and he told me that nitric acid (HNO3) is used to protect the aluminium tanks. Even nitric acid is transported in aluminium tanks.
However, I am not sure if the intakes are pure alu or probably plus some other metals.
He says that nitric acid gives a nice whitish shine and protects the alu. However, as he does not know what the exact specification is for the intakes and the valve covers, he told me first to carefully check it at a small part how the reaction is.
And he would start with a dilution of 10% nitric acid only.
Should wear protective glasses, gloves etc.
Any chemical engineer here who could comment on that?
5-10 Grand Master
I removed most of mine. Then I painted it black.
3 Grand Master
i think someone once suggested paint stripper(was it George M?)
Gone but not forgotten
Super Moderator
Paul,
I got it off already.
But I want to protect the now nice shining aluminium somehow, because if I leave it like that it will oxydize and get darker again. Also it is not that good to have the aly parts unprotected.
So what I was asking what to do after the remving of the cosmoline. I know painting is one possibility, but I find this idea with nitric acid very interesting, if it works.
3 Grand Master
sorry shogun i misunderstood.what about a clear finish or anodizing.One day i think i will paint my valve cover and intake silver with some dark blue highlights on the cover,similar to george
intake = silver valve cover = silver but where highlights on cover are silver mine will be dark blue,maybe also the highlights on the intake
Here's the best idea for both protection and bling factor. Anodize them!Originally Posted by shogun
http://www.focuser.com/atm/anodize/anodize99.html
And yes, you actually can do it at home if you want. But you might just want to bring it somewhere and have them done. Quicker, cleaner and definitely cool!!
-Fred
Fred W
(oo 00 oo)
95 325i
94 540iA
97 Z3 2.8
Super Moderator
Shogun you should be very careful what you do to yours, the
m70 just like the v8's doesn't have a cast aluminum cover. Its a composite material of aluminum,fiber and i believe some magnesium thrown in there too. If you look at a lot of the v8's exposed to coastal environments or snow, salt you see that they are kind of flaking away.. I would only use paint to seal and protect them rather than any nitric acid oxidizing process.
Major Contributor
Dog Gone, that's a big engine!process.
-ashley
'92 525iA / 179k miles / Born 3.92 / ABS / No ASC / stock / North Carolina
Paper Gaskets Suck!
Big, Big Time Poster
Anodizing generally doesn't work will on cast parts. There is too much porosity in the casting and the result terrible. You'll notice the parts in the photo are either machined or sheet metal parts.
Curt.
Curt.
1994 530iT (gone but not forgotten since I see it every day!)
1991 M5
2 Grand Master
sorry shogun i misunderstood.what about a clear finish or anodizing.One day i think i will paint my valve cover and intake silver with some dark blue highlights on the cover,similar to george
intake = silver valve cover = silver but where highlights on cover are silver mine will be dark blue,maybe also the highlights on the intake
that's pretty badass. what kind of paint is that orange? some sort of heat withstanding...
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