Re: bmw-digest V9 #2400

["Michel Drainville" <MDrainville@xxxxxxxxxxx>]

David,the exhaust manifold is not aluminum. Aluminum melts at around 1220F
and exhaust gas temperature can go over that under hard use of the engine
(like on track).
Also, it is impossible to weld aluminum to steel or stainless.
May be he tought it was aluminum because he couldn't stick a magnet on it?
My M42 exhaust manifold (headers) is made of stainless including the flange
and the exhaust tubing also.

On a side note, stainless or aluminum can be weld by a competent welding
shop. TIG welding makes the nicest job.

To prevent this to happening again? The only thing I can think of, is to
check all the rubber supports for the exhaust system to make sure the
exhaust line is attached solidly, and my be take a look at engine mounts
for stiffness, to minimize engine movement under load.

Hope this helps
Michel.