David McCandless asked:

Hi Paul, since the injectors are now on the 'hot side', would the
magnesium further increase the fire risk? BR,Dave McC

"Kent, Russell" wrote:

The ignition point of cast magnesium is 1153 deg F (623 deg C).  I don't
know what Mg alloy Mistral is using, but it's solid-form ignition point
is unlikely to be far different.  If the cowl temps are that high,
you've got other issues...

Reference:
http://www.eh.doe.gov/techstds/standard/hdbk1081/1081tab2.html

Russell Kent

It?s a non-issue.  We didn?t do any high-tech test, but we suspended a piece
of that Mg alloy over a big oil pan full of at least half a gallon of
gasoline and ignited it.  The gasoline burned out and the magnesium had not
ignited.  Furthermore, remember that the manifold is internally cooled by
cool intake air blowing at 60-70 mph on average.

It won?t ignite unless you use a welding torch on it!

The problem with Mg is machining.  The part will not ignite, but the
scrapings may.  Machining speed has to be considerably reduced vs Al, hence
the higher costs.  Casting is also much trickier and few foundries master Mg
casting real well.

Francois

 
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