Advice Request: Refinishing M20 Aluminum Valve Cover?

[firemanory]

Check out pics of people using Steel-It spray paint. Has an interesting effect that is more of a matte finish than shiny, just not sure how different it is color compared to cast aluminum. They tote it as being an alternative to powder coating, and it can also be welded on without having to remove it during racing/emergent situations (not sure about that one but suffice to say it sounds pretty durable).

[r-mm]

Oh my


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[AndrewBird]

Vapor honing. See here:

https://www.r3vlimited.com/board/showpost.php?p=4940134&postcount=46

[r-mm]

I too would like to ponder how to bring the valve cover/intake to as close to prestine, non cosmoline'd alum as possible. Does anyone have a good period photo of a perfect M20 engine bay to use as a starting point?

[earthwormjim]

To have a %100 correct finish you should spray the thing down with cosmoline. When these cars were new the valve covers and intake manifolds had a yellow film of cosmoline overtop. This coating would remain indefinitely, at least until some enterprising individual took a scrubber to it. A pure, bare, aluminum finish was never "original".



Here are some great M20-specific threads on it.

https://www.r3vlimited.com/board/showthread.php?t=310220

http://www.e30tech.com/forum/showthread.php?t=76093

Cosmoline was sprayed on the cars everywhere, not just the engine bay, for shipping across the Atlantic, it is supposed to have been removed upon receiving by the dealer, so no, it's not being true to the car to spray an extra layer on for restoration...

None is supposed to be left on any cars that were sold. A pure aluminum finish, is original, and the way these cars should have been sold.

[FredK]

Hey digger...
Can you elaborate about what Vapor Blasting is all about. I have never heard of that process. Is that a high heat steam shot at a very high PSI that cleans aluminum or removes a layer of aluminum?

Vapor blasting from what I gather suspends glass bead in low pressure water and air and shoots it at mostly aluminum parts, peening the pores mostly shut.

http://noreasterblastworx.com/vapor-blasting/

[ForcedFirebird]

Well, it may be a late model thing or something. I do remember reading about euro-deliveries on new M3's not having cosmoline.

The dealers were supposed to wash it off, and it was actually clear when applied, so that may have been a difficult task to clean properly. I have found over the years, the cheaper the initial price of the model, the less likely it was washed when it got stateside. Problem is (as we all know well) if left on, it becomes very difficult to remove. If you poke around the net there's a lot of gunsmith info about it, and ways to remove it safely. Steam, elbow grease and a hard rubber scraper is all I found that removes it while keeping the paint safe.

[zipzam]

vapor blasting?

Hey digger...

Can you elaborate about what Vapor Blasting is all about. I have never heard of that process. Is that a high heat steam shot at a very high PSI that cleans aluminum or removes a layer of aluminum?

Another enthusiast also mentioned using a stainless steel media blasting material which imparts some stainless into the aluminum so that it gives the surface a more metallic look. Not sure if it also has to be clear coated to protect is as well though.

[zipzam]

Hey Guys....

Thanks so much for everyone's suggestions and sharing your aluminum restoration methods, experience and possible products. Although Cosmoline protection may be very original to many imported BMWs, I think that most BMW enthusiasts still feel that it's an eye sore in the engine bay.

It appears that there's no perfect solution to reproduce the new aluminum casting look. Yes, the old school technique of using wrinkle black paint with machined logos always looks stunning, giving the motor a performance oriented feel. ForcedFirebird, thank you so much for your suggestion of using the product Aluma Blast, which sounds like the closest option to recreating that cast aluminum look. This product sound exactly what I had once heard about but could not remember the name.

Thanks djjerme, for also reminding me to be extra careful about making sure all the media blasting material has been thoroughly cleaned out of all the nooks and crannies inside the valve cover, which could be disastrous if not checked.


Thanks again to everyone for responding!

[SkiFree]

Oh man, I guess that was a faulty memory I had haha

Well, it may be a late model thing or something. I do remember reading about euro-deliveries on new M3's not having cosmoline.

[djjerme]

Just make sure after you media blast it - you hot tank the crap out of it. You don't want any of the media to go through the engine. If doing the valve cover, the oil baffle can hide some left over media.

Also, there is metal protection you can get that is used following an electroplating. It could be used on Aluminum, but I don't know if it seals the surface enough to prevent oxidation.

[FredK]

My Touring is from Germany and has cosmoline on it..

Oh man, I guess that was a faulty memory I had haha

[D.Martijn]

Actually, wasn't cosmoline only sprayed on vehicles destined for export? My recollection, which may be wrong, is that in the European market, since cars did not have to exported via ocean cargo, they were not coated with cosmoline.

My Touring is from Germany and has cosmoline on it..

[FredK]

Actually, wasn't cosmoline only sprayed on vehicles destined for export? My recollection, which may be wrong, is that in the European market, since cars did not have to exported via ocean cargo, they were not coated with cosmoline.

[SkiFree]

To have a %100 correct finish you should spray the thing down with cosmoline. When these cars were new the valve covers and intake manifolds had a yellow film of cosmoline overtop. This coating would remain indefinitely, at least until some enterprising individual took a scrubber to it. A pure, bare, aluminum finish was never "original".



Here are some great M20-specific threads on it.

https://www.r3vlimited.com/board/showthread.php?t=310220

http://www.e30tech.com/forum/showthread.php?t=76093