Magnesium Parts

[ddalder]

I recently found out the hard way that the cam covers on my LD8 are not aluminum, they're magnesium. Recently I tried to order a new left cover. GM told the dealer it would be on the way soon, there was just some sort of hang-up with the manufacturing facility. A couple of weeks later GM told the dealer the order was canceled and I will not be receiving the item. I haven't been able to find a new one on eBay and no GM dealer in Canada or the US has one. I'm not sure what's so different about these ones compared to the other zillion years of the LD8/Northstar, but they only fit the 2004-05 Bonneville, 2004-05 Cadillac DeVille and 2003 Cadillac Seville.

So... off to the wrecker. I found one and removed it then had it ultrasonically cleaned. The problem was that it needed to be refinished. I took it to a plating company and they dipped it in a tank of stripper for aluminum parts. Well, it started bubbling immediately as the solvent began eroding the magnesium. Sigh! They took it out of the tank right away but some damage had likely been done. Most of the finish that was on it is gone which is fine. I'm just concerned about some of the sealing surfaces. Perhaps I should look for another used cover and start the process over again?

Next problem... A powder coating company I contacted said they can't help me with finishing because powder, ceramic and other finishes they have won't stick to magnesium and suggested I use an automotive paint of some type. If I use a high temperature paint I may be okay. I'm just not sure I'll get the finish to a standard I want.

Any thoughts, suggestions or experiences with magnesium anyone???

[00Beast]

I know it is easily flammable. The early drag racers used magnesium for their wheels (hence *mag* wheels) and if the brakes got to hot sometimes the wheels would violently combust!

What's wrong with your current cam cover? Warped or cracked? Or does it just need refinishing?

[ddalder]

I want to replace the gasket for the usual leak problems. I haven't had a problem since I used a Felpro gasket on the right cam cover so I'm hopeful changing this one will have an equally positive result. I really don't want to put a cover back on that doesn't look new. Half the reason repairs sometimes take me a long time is because I clean and detail the crap out of everything during reassembly.

[00Beast]

Right, I get that. Could you swap this cover on for a bit with the old gasket, or rags over the cams, to keep the crud out while you take your stock cover to be refinished? Unless you're afraid that the cover is warped or damaged somehow.

[Wes]

Can you electroplate the magnesium in copper or nickel first and then have them powder coated?

[ddalder]

Right, I get that. Could you swap this cover on for a bit with the old gasket, or rags over the cams, to keep the crud out while you take your stock cover to be refinished? Unless you're afraid that the cover is warped or damaged somehow.

Under normal circumstances, that would be a possibility. Unfortunately, I'm trying to get it ready to put in storage for the winter. I want to park it next week and that just won't leave me enough time.

Can you electroplate the magnesium in copper or nickel first and then have them powder coated?

That's an interesting question. This may be a possibility but I need to do a little more research first. Once I know, I'll post back in case anyone else runs into a similar problem. I do know that magnesium can be chromed but must be dipped first for similar reasons.

[redfury]

I never plated magnesium, but usually I would clean with triclorethelene, rinse and drop it into a copper tank to flash copper on it as a primer and then go into the electroless nickle and then onto whatever was going to be the finished plating. If the part still has sharp edges and no signs of pitting, then I think you'd be okay with it, but I would definitely want to do more research about dealing with Magnesium parts.

Did you tell the company that dipped it that it was magnesium when you handed it off to them? Seems weird that they would treat it like Aluminum, unless it was just a mistake ( which happens ).

[ddalder]

To be perfectly honest, I assumed it was aluminum based on weight and rigidity so I told them it was aluminum. I've actually been considering finding a set of them and seeing if there's anyone out there that will apply a black chrome finish. I found a website for a company that does this, but I get the impression the only process new parts for manufacturing companies. Apparently they process the magnesium paddle shifters for GM's ATS.

[DRWBRTq19]

Interesting.
For what it's worth, I had mine powder coated a year ago.

https://photos.app.goo.gl/koFn3ojHFECRDI6s2

https://photos.app.goo.gl/c02nUkx6pdXONXGN2

(can't get pics to work, so just follow links... sorry)

Drew

[ddalder]

I know this is kind of old now, but did you ever have any problems with the finish since this was done?

I noticed the other day that the cam cover, previously canceled by GM, was still listed as active on many online parts sites. I asked my dealer to check again. It seems that GM had some change of heart and must have had more made. They are now available again and I have one on the way.