Club Cobra - Modern Magnesium Halibrand Wheel Quality

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Anyone know if the newer 'miracle' alloy magnesium (not the whole wheel, the raw magnesium) comes from offshore? Xracer, do you have any info on that? I would think if they are made with more alloys added to the mag, they would be heavier. If it's a'purer' grade of mag then not.

Rod,
Really now only takes less than a half hour to do all four wheels with PB and M.Buffer. And you can do it every 2 months with no problem or loss of shine.

Quote:

Originally Posted by RodKnock (Post 932014)

Doug, I believe the wheels sold new for $765 per wheel for the fronts and $795 per wheel for the rears, when they were available from Halibrand.

So add in some decent tires like Avons and you're bumping up against $5k out the door. Wow! Good looks, originality and all, but???

Quote:

Originally Posted by Got the Bug (Post 932034)

So add in some decent tires like Avons and you're bumping up against $5k out the door. Wow! Good looks, originality and all, but???

Well, if you're trying to make a more accurate replica...:LOL:

Agreed, it's a ton of money. :CRY:

Regarding the quality of wheels made today and from "back in the day", I believe the magnesium alloy is slightly different and a touch heavier than the early days. I met Ted (owner of M&A) when I was racing the Indy Lights cars that he had the exclusive rights to produce the wheels for. He is a very nice guy and has been in the magnesium casting business a long time. I think they do use pressure when casting now, not just pouringinto the mold which helps eliminate voids, leaks, etc.

If you've ever been to a magnesium foundry, they are not real pretty places. They are in one of two categories: One that has burned down or one that will burn down. As such, not a lot of investment into the facilities other than what is necessary to get the job done. I have been to M&A in Pinconning MI and it is as good as it gets in that business. Where they are really good is the machining side. Their wheels were great on the racecar and could take a good whack, (see pic in my gallery) easy to balance.

I just wish he would market the cobra style wheel himself, but I'm sure he wants to protect the relationship with his customer Halibrand.

Bob, do you know how long Halibrand has been an M&A customer? Put another way, how long has M&A been making the Cobra II wheels for Halibrand?

That I don't know for sure but he was doing them when I was racing the Indy Lights cars from '91-'96. It may have been much longer than that.

[quote=Also, it's beyond me how a new process using real magnesium can produce a product that stays shiny - magnesium seems to be like rust - it's alive and never rests.[/QUOTE]
It wouldn't be the process, but the formulation of the alloy. Magnesium is one of the most "active" metals there is. Kind of like a cheap hooker, it wants to couple with almost everything around it!:eek:
Aluminum actually protects itself by corroding. The resulting oxide (known as rust on iron) seals the underlying metal against oxygen in the air and protects it from further corrosion. I believe the process is similar with Mg. So when you polish off the oxide you're actually removing the protective coating and exposing the metal to additional corrosion. Better to seal it and skip the polishing (at least with Al).

Warren,
About 5 years ago I sent mine to a polisher where the centers were fine oxide blasted and the machined rims were repolished. When I got them back, I used Duplicolor clear to coat the centers only to preserve the original soft gold/green. Due to brake heat the centers turned dark gray again under the clear. The clear is still intact.
Do you know of an effective coating for Mg?

ERA Chas

If I remember right DOW have some coating. (I like this light yellow color)

http://www.dow.com/oxysolvents/app/coatings.htm

The FIA have a material list for Magnesium alloys.

http://www.fia.com/resources/documen...als_a_2004.pdf

I found the link of the FIA page on the Vintage Engineering site

http://vintageeng.com/

Good luck

Thank you Walter for a long-distance reply! How is George's stroker in that beautiful ERA?

Chas

Thank you for the flowers.
George built for me a wonderful engine that make a lot of fun to drive on Swiss mountain roads.
Unfortunately since November we have about 30°F and the car must sleep in the garage. (excuse my bad English)

Quote:

Originally Posted by WarrenG (Post 933682)

So when you polish off the oxide you're actually removing the protective coating and exposing the metal to additional corrosion. Better to seal it and skip the polishing (at least with Al).

The centers of the Halibrand wheels are coated with a Dow paint/coating, but it's the outside rim that will corrode, including the part that gets covered by the tire. So, you're saying to leave the outside corrosion alone in order to preserve the magnesium rim? No polishing recommended?

I'm beginning to think it's more work than it's worth.

The book I have recommends an acrylic or vinyl acrylic coating baked on for maximum adhesion for aluminum and magnesium. It states that most instances of oxidation after coating have been due to failure of the coating (sometimes pinholes not readily visible to the eye) that allow oxidation of the metal beneath the coating. If the magnesium is changing color due to brake heat, I'm not sure what (if anything other than cooling air) would stop that.

Lots of reading but you asked. Go to www.roadsters.com/wheels. Then go down to topic ( care of magnesium wheels ) at bottom of topic click on Gibbs Brand.

Quote:

Originally Posted by ERA Chas (Post 931731)

Rod,
I mis-spoke earlier, my wheels were bought in 1991 when Barry Blackburn owned the company and just before he sold it-so they're 18 years old.

My local area is generally damp most year 'round and I'm less than 4 miles away from salt water and oxidizing was really a problem. If I didn't polish twice a month they'd get to the point that 0000 steel wool and polish was necessary. I hated the hand polishing but letting them turn just slowly destroys them and I can't replace them. A tip from Cobraviper-99 on here led me to try the Powerball and Mr. Buffer. They literally have not turned cloudy since December-over three months. And it's so much easier, so corrosion is just not a problem for anyone anymore.

These wheels have always had bias Hoosiers which leaked 2-4 pounds per week, Billboards which leak the same and very briefly, Dunlop radials which never leaked.
As razer suggests, epoxying the inners is a good move but mine were never coated. All of my air losses have been from the tires.

Never weighed the individual rims but the combined weights of wheel and tire with Billboards is 35 pounds front, 41 rear. I never had aluminum wheels to compare so I don't know how much lighter the mags are but it's substantially noticeable. A friend has PS aluminum FIA's which are significantly heavier. I had them on the car briefly and they look super on a 427 car but even wearing Billboards they were freakin heavy by comparison. They too do not leak air with Avon radials.

Bridge Hampton and Westhampton are gone so I haven't been to a track since '04. Yes, I'm all over the wheels frequently for cracks visually (don't have a Magnaflux) especially the inner hub face contact area. Nothing. I do have a couple of dings from missed hammer hits and that's with a lead hammer so they are soft. Street driving has not hurt them. They balanced pretty well with 2 of them requiring no weight. I have one really bad rear g
G'year with about 4 oz on it-not the wheels fault.

Can't speak for M&A wheels but I have read that they make quality castings. Would like to know more about them. Vintage wheels has an excellent reputation that I've read but they don't cast mag to my knowledge-only aluminum. Wonder why they don't cast mag offshore at friendly prices like their aluminum?

These are my experiences-love to read others mag experiences.

If you clean the wheels and dont apply wax you can spray them with semi gloss clear coat and that will be the end of your corrision problem. Good Luck Larry Spillman

Quote:

Originally Posted by Larry Spillman (Post 1045276)

If you clean the wheels and dont apply wax you can spray them with semi gloss clear coat and that will be the end of your corrision problem. Good Luck Larry Spillman

Thanks for digging out this old thread Larry.

As I stated earlier I have cleared my centers after they were blasted and the clear is still intact today. They have grayed from heat but not corroded. I clean the centers with WD 40 and the brake dust comes right off and the clear is still glossy.

The rims require the most effort on the inner sides as I don't pull them every month. The brake dust kills them after a season and requires med grade steel wool, followed by fine and polish to get them back. The fronts are done much more frequently because it's so easy on the car. Never wax them because it won't do much and heat will eat the wax. Polish with Mothers first followed by Mr. Buffer. Much faster with Powerball.

They stay very nice and only get cloudy and gritty when there's a long wet or humid spell.

Quote:

Originally Posted by ERA Chas (Post 1045291)

Thanks for digging out this old thread Larry.

Yea Larry, thanks. :rolleyes: Thanks for reminding me that I don't have mine yet. :CRY:

Halibrand went back "under" and hasn't returned a couple recent emails of mine.

Quote:

Originally Posted by RodKnock (Post 1045292)

:rolleyes: Thanks for reminding me that I don't have mine yet. :CRY:

:LOL::LOL::LOL:

Wanna trade that purty ally body for my purty Mg?

Quote:

Originally Posted by ERA Chas (Post 1045297)

:LOL::LOL::LOL:

Wanna trade that purty ally body for my purty Mg?

I know how this story ends. It's the old "five magic beans for a cow" story. I know how this one turns out already. :LOL:

Yeah-but you may meet the giant's sympathetic, lonely, lovely wife... %/