Cosmoline, the yellow stuff on your engine

[shogun]

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?

[Jon K]

I removed most of mine. Then I painted it black.

[Paul in NZ]

i think someone once suggested paint stripper(was it George M?)

[shogun]

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.

[Paul in NZ]

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

http://www.bimmer.info/bmw/kiwi535/M-30PassSdResize.jpg
intake = silver valve cover = silver but where highlights on cover are silver mine will be dark blue,maybe also the highlights on the intake

[FWinNH]

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.

Here's the best idea for both protection and bling factor. Anodize them!

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

[Bill R.]

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.http://www.bimmer.info/%7Ebill/m70valvecovers.jpg








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.

[granit_silber]

process.http://www.bimmer.info/%7Ebill/m70valvecovers.jpg

Dog Gone, that's a big engine!
-ashley

[Springfield1952]

Here's the best idea for both protection and bling factor. Anodize them!

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

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.

[angrypancake]

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

http://www.bimmer.info/bmw/kiwi535/M-30PassSdResize.jpg
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...

[Springfield1952]

that's pretty badass. what kind of paint is that orange? some sort of heat withstanding...

There's no need for any special paint on the valve cover since it doesn't get that hot. Any good enamel such as Krylon or Rustoleum will work fine. Some have powder coated engine parts which is the most durable but also the most costly.

Curt.

[Jeff N.]

I got the cosmoline off my aluminum parts with hardware store paint stripper and a scour pad.