Magnesium Burns.... its crying time

[Indescikov]

Pictures speak for themselves




It was a beautiful and very perfect 1970T... no rust and original owner.

[MARISOL78sc]

Ouch, hope owner had agreed insurance policy.........

[tdw28210]

HOLE - LEE SHIATZU! That is tough to look at. Amazing to see metal just deleted by flames.

[pete3799]

Wow.......and I was bummed cause I hit a deer with mine.
Sorry for your loss.

[Discseven]

Inde.... That is downright awful. Wish I had something good to say but am totally down looking at this and feeling for your loss.

[fanaudical]

I'm sorry for the loss of your 911. I hope no one was injured in this.

Any ideas how this started? Perhaps there is something for the rest of us to learn and hopefully avoid in the future.

[Indescikov]

It is not mine but belongs to a good friend.
He attempted to put it out with a Halon extinguisher, it initially went out but relit. When it did he ended up with second degree burns. The fire department "drowned it" with water, hot magnesium was shooting out of the bottom of the engine.
The fire department said it did not look like a gasoline fire. It was concentrated on the driver's side and around the fan/shroud/alternator. At initial look, it might be an electrical fire. Just for note, all the fuel lines were virtually new and these were PMO's carbs. This was a very well maintained machine. The fuel pressure gauge is still readable and is frozen at about 10psi!
Any other ideas?
This is why I am posting this... food for thought especially considering old machines with compromised electrical systems and perhaps obsolete designed electrics (sorry)
Anyone consider fuseable current limiters at the batteries and alternator wire from the starter?
I have a friend with a very expensive restoration and he has just such current limiters on this battery and alternator. They are a common components in aircraft electrical systems. (Beechcraft for example)

[manbridge 74]

Tough break.

Under what circumstances did it occur?
Right after fuel line work?
Spring startup?
While parked after a drive?
Recent engine out?

I'd think if the large wire from alternator to starter shorts to ground it wouldn't generate enough heat to ignite magnesium.

Do PMOs need 10psi? Seems high.

[fanaudical]

I'm sorry to hear your friend got hurt. I hope he heals quickly.

I think I agree with Jeff. If the main wire from alternator to starter cable got shorted, I would think that wire would burn out first. Maybe it shorted to a portion of the fan shroud, which in turn ignited as it carried current to ground?

[Rawknees'Turbo]

Originally Posted by Indescikov

This is why I am posting this... food for thought especially considering old machines with compromised electrical systems and perhaps obsolete designed electrics (sorry)
Anyone consider fuseable current limiters at the batteries and alternator wire from the starter?

The 911 electrical systems, all the way through at least 1989, are total jokes when it comes to things like adhering to basic, electronics 101 best practices (change that to "worst practices" and you've got what the 911 designers worked by!); many 911s have partially, or completely, burned due to the factory nonsense of not fusing live circuits (dash lighting, various hvac system components, one fuse for two, high current drawing fuel pumps on Turbo models - and the list goes on an on). It's definitely wise for owners to correct as much of that as they can. I've done all the wiring mods that I know of to my 1987 Turbo, but am going to look into the current limiters that you mentioned - seems like a smart step!

[Bill Douglas]

Sorry to your friend for his loss

With the value of these cars being what it is, probably if could be rebuilt other than being parted out.

It's strange that the tail light lense has stayed intact considering how hot a magnesium fire is.

[Indescikov]

Just to clarify, the fuel pressure was set correctly at 3 to 3.5 psi

[kiwiokie]

Makes me think about the battery cutoff switch I have yet to get around to installing....

[RichardNew]

I have an article in this month's Vintage Motorsport magazine that deals with magnesium fires.

Magnesium is a Class D fire:

Class D: These fires occur in combustible metals such as potassium, sodium, aluminum, and magnesium. If you have an Indy car with magnesium wheels and an aluminum body you’re going to need a class D extinguisher. Aluminum and magnesium truly complicate your choices since the average home extinguisher only works on A, B and C fires. You’re going to need a special extinguisher for Class D fires.

I'm surprised that the fire company tried putting it out with water. They probably didn't know it was magnesium. Halon is useless on a Class D fire.

Richard Newton
Insurance 101

[tirwin]

Originally Posted by RichardNew

I'm surprised that the fire company tried putting it out with water. They probably didn't know it was magnesium. Halon is useless on a Class D fire.

Not surprised at all. I bet it never even occurred to them. There is a video that has been posted here a few times of firefighters hosing down a magnesium block car fire. it made quite a show.

Probably was Halotron and not Halon. Halon hasn't been manufactured for a long time because it's a CFC.

Very sorry for the loss and I hope the owner is ok.

[GothingNC]

I am friends with the owner, he sent me an email about the fire.

Shame since he owned the 70 911T since new :-(

I am glad he is Ok and his burns were not 3rd degree.

[Jerome74911S]

I'm curious to understand what caused the fire to go out. Once magnesium really gets going, and we can see where some of it has burned away, would "drowning it" with water actually cause it to stop burning? Why would it go out otherwise? I don't know enough about burning metals to know what happens, but in any case I thought water would just increase the fire.

Who is able to explain this?

[timmy2]

A very sad day...
Another reason to swap out those 40+ year old engine harnesses. They take the most abuse of any of the electrical systems in our cars.
Unfortunately I've built many of them for insurance claims due to fire.

[manbridge 74]

Probably a slurry of some sort. Mag will burn underwater.

[dtw]

Wait a minute...is this Gary's car? Is he alright??

Originally Posted by GothingNC

I am friends with the owner, he sent me an email about the fire.

Shame since he owned the 70 911T since new :-(

I am glad he is Ok and his burns were not 3rd degree.