Re: [alfa] aluminum exhaust manifolds

[Stacy Faught <onethumb@xxxxxxxxxxxxx>]

"I was just wondering today why alfa didn't use
aluminum for the exhaust
manifolds?  Maybe it's just a dumb question, but why
use aluminum for the
entire engine and transmission and then cast iron for
the exhaust manifolds?
They sure made some nice looking cast iron ones tho, I
like the way the
early ones are split 1-4/2-3
___
  /<>/>/>
77 spider
Boston, MA"


Aluminum has a melting point of about 1200 deg. F,
which is also just about the same as the temperature
of the exhaust gas under normal load.  I believe the
exhaust gas temp can get as high as 1400 or 1500 deg.
at WOT.
Iron, on the other hand, has a melting point far above
that (2800F, I believe??)

If you devised a cooling method for the outside of the
headers, then you could make it work, but then you'd
be slowing down the exhaust gasses....

This is of course why it is so critical to keep the
cooling system in our cars in top order, and why they
warp so easily compared to cast iron engines.


Stacy Faught
'87 Spider Quad (not melted)
'78 Alfetta Sport Sedan (attacked by the tree sap
monster YET AGAIN!)

PS:  Does anyone know a reasonable way to get tree sap
off your beloved car's paint job?  I hate sappy
trees...I'd be much happier if they were all stoic.
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