re: Cracking exhaust manifolds

[Jay Negrin <jmnegrin@domain.elided>]

Stefano -

How many miles do you have on your manifold?  I have a similar set-up on
my Alfetta GT.  The first set I had broke because I smacked the front of
the car on a too-steep driveway at somewhere about walking speed.  The
flange did not break, but the 1 - 4 manifold piece ended up with an
annular (of that's the right word) crack, which effectively made the
whole affair three pieces instead of two.  New manifold, and I'm back in
business.  Except for that largish rock I hit on the club's spring tour
in late March.  Bashed the catalytic converter rather thoroughly.  As
far as I can tell, the manifold is still OK.  The loosening nuts on the
header flange may be telling me something, though.

In your case, I might want to examine the fit from the manifold to the
head.  If possible, try this without the manifold bolted the header pipe
(that two-into-one welded up tubing thingy just aft of the cast iron
manifold).  Is it possible that something isn't aligned properly?  If
the manifolding bolt holes line up with the studs on the head, that may
be a clue.  If you have an old head lying around, the test-fit is a
whole bunch easier.

As the seargent in Hill Street Blues used to say
"Be careful out there."

Jay Negrin
ARO So Cal


Date: Fri, 21 Sep 2001 19:37:26 -0700
From: "Stefano Iachella" <iachella@domain.elided>
Subject: Cracking exhaust manifolds

Hey cats,

My Euro cast iron exhaust manifolds have cracked at the mounting flange
for a second time. These are the two piece ones for Alfettas. It cracked
first around the forward stud hole of #4 cylinder, and now around the
rearward stud hold of the same cylinder.Curious to see if any strange
stresses were acting, I removed it myself this time. It was hard to
remove and when it cleared the studs, the whole manifold shifted forward
about 1 cm. (1/2 in).  Just to slide it back on the studs required a
heavy push backwards; I almost couldn't do it myself. Could this be why
it's cracking so?

Thanks,
Stefano
Oakland, CA

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