DeTomaso Mailing List: April 1997, Message #129
     



From: "Charles F Engles Jr." <engles@qns.com>

Subject: Re: Benefits of Campagnolo wheels

Date: Wed, 16 Apr 1997 19:44:48 -0500



Dear Andy,



I am no engineer nor a metalurgist (sp?).  I would defer to a more expert

opinion on the strength and brittleness of aged magnesium.  Your points are

well taken.   There is a way to check the Campys structural integrity and

that is the Zyglo method.  Its primarily used in aviation.  It involves

taking the wheel and heating it up.  Then its painted with the zyglo

compound and allowed to cool.  Its washed and then placed under UV light.

Any hairline cracks expand with the heat, fill with zyglo and are revealed

with the UV.  I had it done on one of my wheels after it had been abused at

the tire store  (they paid for the expense) seems like it cost about $75.

Seems like I recently read in this forum, that the flammability of

magnesium wheels was greatly overrated.  As I recall the typical

temperatures generated in a normal gasoline powered car crash and fire are

too low to ignite magnesium.  Playing devil's advocate I would offer the

observation that in the last twenty five years of Panteras and Pantera

accidents, that they have an infamy in many areas, but flammable magnesium

wheels doesn't seem to one of them.

Perhaps Ted Mitchell can comment.



Chuck Engles



----------

> From: Andy Poling <andy@realbig.com>

> To: Shane F. Ingate <pantera@shiseis.com>

> Cc: detomaso@wgate.com

> Subject: Re: Benefits of Campagnolo wheels

> Date: Wednesday, April 16, 1997 2:34 PM

>

> On Wed, 16 Apr 1997, Shane F. Ingate wrote:

> [...]

> >         Lets talk Campys.  Campys are magnesium, which is

> > considerably lighter than aluminum.  Lets say a Campy wheel weighs

> > 5 lbs less that an equivalent aluminum wheel.  This is equivalent

> > to a saving of 200 lb is weight for the car, which means you

> > free up 30 hp by sticking with the Campys.  30 hp is noticable!

> >

> >         A good argument for staying with the Campys.

>

> I considered that for a while before I ordered the Wilkinson repro

Aluminum

> wheels, and I hated to give up the lightness.

>

> On the other hand, Magnesium has several traits that scare me.  First the

way

> that they corrode if the Magnesium is exposed to the air (including

inside

> where you cannot see it).  Second, the fact that Magnesium burns *very*

hot

> (flashes) if ignited... like in a really bad track accident.  Lastly,

those

> Campy's are 25 years old - I have doubts about their strength vs.

> brittleness.  I don't even know if you can test them in any non-intrusive

> way to ascertain whether they are still wholly intact and strong.

>

> I'll take the weight in exchange for a new wheel that won't corrode at a

> spectacular rate if scarred and won't flash into a very hot flame when

> ignited.  The repros I ordered are also larger: 8x16" front and 11x17"

> rear... that's worth some time too. :-)

>

> I just wanted to make sure we looked at both sides of the coin...

>

> -Andy

>

> 72 Pantera: power             91 Miata: quickness              96 A4Q:

traction

>                             84 RZ350: all the above