The manifolds differ only in the thickness of the flange where the manifold
attaches to the head. Off-hand, I can't remember what years which
thicknesses were used on - and, frankly, it doesn't really matter. So long
as the intake manifold has the same thickness flange, all will be well and
no leaks should be encountered. It's always a good idea to place a straight
edge along the head side of the manifold flanges, however, as heat can warp
them. If they are not flat, then they should be made so on a belt sander.
This is particularly true of the Z-S combined manifolds, where the heat from
the cat plays havoc with the metal.
Lawrie
British Sportscar Center
-----Original Message-----
From: wizardz@maxinter.net <wizardz@maxinter.net>
To: MG List <mgs@autox.team.net>
Date: Friday, April 30, 1999 9:19 AM
Subject: flanges are different???
>Hi all....
>Hey Lawrie... I pose this question to you more than the rest of the list
since
>I assuming you have ... at least... seen a greater variety of exhaust
manifolds for
>different vehicles.
>
>I just this morning noticed a variance in the two exhaust manifolds I have
>sitting about. Specifically I've noticed a difference in the thickness of
>the mount flanges. Both are the stock type 3-to-2 cast iron.
>
>One unit says 'MOWOG' on the rear down tube with '12H709' on the front tube
>this unit has a flange thickness of roughly 0.56"
>
>The other unit says 'AGA E1' (where the other said MOWOG) and it's forward
tube
>says '12H 3911' This one's flange is only 0.43" thick
>
>I've not had a chance to measure the thickness of the intake manifold for
the SU's
>
>Since neither is on a car I'm not sure which of my two GT's either came off
of.
>I'm assuming the true MOWOG unit cam off of YB (my primorse GT) since it
had
>a Weber downdraft andstock exhaust on it as purchased and the 'PIERCE'
manifold
>for the Weber has a flange thickness of roughly 0.57"
>
>Other than the flanges...they are almost indistinguishable from one
another.
>why do I wonder about this?
>
>I guess in properly mounting them.. or if one were to end up with one of
these
>it would make getting a good gasket seal rough.... as the thickness
difference
>as compared to an intake manifold would not allow the stubs to hold both
>tight to the head if the thicknesses were this much different.
>
>I guess I'm asking if you have ever run into something like this.
>
>Paul Tegler
>Twin 73' MGB GTs YB and OB
>YB born 8/72 (Primrose Yellow) Yellow BGT
>OB born 1/73 (Blaze Red) Orange BGT
>North of Annapolis, South of Baltimore
>email: wizardz@maxinter.net
>http://www.amdyne.net/~ptegler/mgmain.htm
>
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