What is the Silver Finish on the Intake?
 

So, I'm preparing for my next (and hopefully last) trip to a garage to get the carbon cleaned out and I thought I'd have the intake cover repainted at the same time.

I always thought engine covers were powder coated, but a powder coater in Milton Keynes suggested conventional paint instead because the heat can make powder coats blister.

They offer a number of different types of colour - from powder-coating to painting and anodising, so I thought I'd ask what the factory finish is?

Is it painted, or powder coated?

In case I have the terminology wrong, I mean the bright silver bit in the attached pic. In between the Audi rings cover and the V10 5.2 cover.

http://media.caranddriver.com/images...cd-gallery.jpg

On my D2, as with some other, older cars, the finish can start flaking off suggesting it is a painted finish applied directly onto the cast aluminium/alloy manifold. I and others have used high temperature aluminium spray paint to refurbish it. I should have completely stripped it before painting as the flaked areas still show under close scrutiny but couldnt afford to dissemble it and get it shotblasted/dipped or whatever at the time.

I think its raw magnesium on the s8 manifold

Hmm... I did briefly consider going over it with some high temp paint but I couldn't stand the thought of it being a more dull silver. I like how bright it is.

Raw magnesium? Holy cow, isn't that the stuff that used to epically burst into a purple flame in my high school chemistry lessons?

Has anyone had theirs resprayed/refurbed? What did you do and did the finish last?

"raw" magnesium it aint! Mag alloy is used in some aircraft/helo parts (wheels etc) to reduce weight but it comes with problematic fire issues requiring specific firefighting equipment (Delboy - ask your rigs FF teams). So its probably not used for intake manifolds.

The high temp Alu paint I used gave it a finish close to the original which, considering its a "rough" cast finish, is never going to be got to a high shine finish.
There is a thread on here somewhere where someone (who is now PNG on this forum) showed a manifold refurb process.

I found the thread - its a sticky under D2 Engine Bay BUT whilst showing the acid bath treatment it doesnt state what finish was applied. :(

Yikes, I just realised I somehow managed to post this in the D4 section! Wow, that's two for two.

Thanks very much for your input, David. Do you have any before/after pics of your engine?