Lotus Elan

Magnesium components lifespan

PostPost by: 661 » Sun Mar 06, 2016 7:09 pm

I was speaking to an engineer the other day and he casually threw in that the magnesium race components he manufactured had a lifespan of about 10-15years.
I didn't go into more detail as we were dealing with another matter, but what does this mean in terms of rebuilds?
Those circlip holders on the hub carriers, do they crumble? Does the gearbox casing become so brittle that it needs throwing away. And of wheels? Slightly more pressing to ensure they are up to the job.
I'm not aiming for front of the grid but I'd like the car to be competitive without having to replace major components in 10 years because they are time expired.
What's the pragmatic view?
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PostPost by: Elan45 » Mon Mar 07, 2016 2:34 pm

I/m still using original components on my 1958 Lotus Eleven. I've had one wheel on the Eleven fail, back about 1992. I could see a crack forming and replaced the wheel w/ another original Eleven wobbly. I'm still running the original bearings directly in the front wheels, so no one makes replacements of those. Add lightness goes way back in time.

And also some mag components on my 20'22 Formula Junior. Never a failure, but the rear uprights and wheels are all Bill Halandal/ Don Schafer new US products in 2001.

I was told 30 years ago that if a mag part had a problem, it would show up under visual examination. So, I do a lot of close examination at home and things like wheels each day or more often at the track, when torquing the wheels before each session.

Roger
'67 Elan S3 SS DHC
'67 Elan FHC pre-airflow
'67 Elan S3 SE upgrade to 26R by Original owner
'58 Eleven S2 (ex-works)
'62 20/22 FJ (ex-Yamura)
'70 Elan +2S RHD
'61 20 FJ project
'76 Modus M1 F3
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PostPost by: 661 » Mon Mar 07, 2016 8:41 pm

That's useful and reassuring to hear, thanks Roger.
I wonder it things like epoxy paint or POR 15 slow the oxidation process?
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PostPost by: StressCraxx » Mon Mar 07, 2016 8:57 pm

661 wrote:That's useful and reassuring to hear, thanks Roger.
I wonder it things like epoxy paint or POR 15 slow the oxidation process?


In my experience on magnesium, paint or powdercoat merely hides the corrosion underneath. I was warned of this by several vintage racing preparation shops.

The existing oxidation must be removed either by polishing or abrasive blasting such as baking soda, walnut shells or other gentle media. The conversion coating must be applied quickly before oxidation forms again on the surface.

A product called Alodine (chromate coversion) treats the magnesium alloy surface and provides a passive layer to oxidation. The treated surface can be painted with clear coat to preserve the passive layer.

Alodine is available through aircraft home builders vendors, but be warned, it is highly toxic, requiring gloves, goggles, skin and respiratory protection with a good sealing vapor mist mask from the fumes. This stuff (hexavalent chromium) can be absorbed through the skin, mucus membranes and lungs. Read the MSDS data sheet.

Lets face it. Race cars were originally engineered to last no more than one or two seasons, then discarded or sold. Anything beyond that is a bonus, so inspect frequently for your own safety.

Regards,
Dan Wise
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PostPost by: Chancer » Tue Mar 08, 2016 9:11 am

Wise words.

What else would you expect from someone with Wise as a surname and Stresscraxx as a username :lol: :lol:
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PostPost by: Elan45 » Tue Mar 08, 2016 2:33 pm

I started racing my Eleven in 1989 w/ beautiful wheels painted yellow w polished rims and the whole wheel covered by whatever clearcoat recommended by Ditzler. The clear over the bare mag rims started discoloring and pealing within 2 years. The yellow paint, applied over DP40/401 epoxy primer lasted a little longer, but soon looked like brake fluid had been spilled all over. The wheels are the ugliest part of the car.

So, for the FJr wheels, II changed primer, because I found in Ditzler literature, that DP40 was an etch primer. I'm not in my shop, so I can;t remember right off what I changed to, but instead of polishing the of polishing the rim lip, I painted it w/ silver, then masked the rim and yellow on the wheels. Worked much better, but some of the wheels are starting to have the brake fluid look. I'm thinking of hand sanding the wheels before a repaint.

While researching the covering for the FJr wheels, I came across a company that could anodize magnesium. I believe they only wanted to work on new mag and I believe it was not inexpensive. I also tried other paint companies such as Dupont and ICI, but settled on the above.

It'd be nice to know what Dymag and Compmotive use that maintains that nice blackish brown.

I won;t use powder coat on anything!

Roge
'67 Elan S3 SS DHC
'67 Elan FHC pre-airflow
'67 Elan S3 SE upgrade to 26R by Original owner
'58 Eleven S2 (ex-works)
'62 20/22 FJ (ex-Yamura)
'70 Elan +2S RHD
'61 20 FJ project
'76 Modus M1 F3
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PostPost by: StressCraxx » Tue Mar 08, 2016 8:23 pm

Chancer wrote:Wise words.

What else would you expect from someone with Wise as a surname and Stresscraxx as a username :lol: :lol:


Could you imagine what it was like going through school with a name like that? Even the teachers used it for ammo.
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PostPost by: StressCraxx » Tue Mar 08, 2016 8:26 pm

Elan45 wrote:I started racing my Eleven in 1989 w/ beautiful wheels painted yellow w polished rims and the whole wheel covered by whatever clearcoat recommended by Ditzler. The clear over the bare mag rims started discoloring and pealing within 2 years. The yellow paint, applied over DP40/401 epoxy primer lasted a little longer, but soon looked like brake fluid had been spilled all over. The wheels are the ugliest part of the car.

So, for the FJr wheels, II changed primer, because I found in Ditzler literature, that DP40 was an etch primer. I'm not in my shop, so I can;t remember right off what I changed to, but instead of polishing the of polishing the rim lip, I painted it w/ silver, then masked the rim and yellow on the wheels. Worked much better, but some of the wheels are starting to have the brake fluid look. I'm thinking of hand sanding the wheels before a repaint.

While researching the covering for the FJr wheels, I came across a company that could anodize magnesium. I believe they only wanted to work on new mag and I believe it was not inexpensive. I also tried other paint companies such as Dupont and ICI, but settled on the above.

It'd be nice to know what Dymag and Compmotive use that maintains that nice blackish brown.

I won;t use powder coat on anything!

Roge


Could it be this?
Used by Indycar teams on critical components.
http://www.kecocoatings.com/coating/kephos-coating/
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