>place, and I tightened the rest. It'd do, and there was no movement
>when I wiggled on the exhaust system.
>
>Which has just now come back to bite me. You see, the header is
>meant to be loose so that you can fit it over both of the studs that
>act as locating pins, the ones at the extreme ends (the rest of the
>studs locate both manifolds, and therefore have cutouts but not
>holes). With the header bolted down tight to the downpipe, I can't
>get the header to align with both holes -- I can line up the rear just
>fine, but no amount of levering or lifting will get the front to line
>up. And I can't really get the front high enough even with the rear
>stud removed. So (sigh...) I'm going to have to loosen the flange and
>frob with the header before this car makes noise. Damn.
I had exactly the same experience with my MG. It's really difficult to
get at the manifold to downpipe connector when the manifold is on the
engine block. So the solution would seem to be to tighten it before
putting the manifold back on, however this makes the manifold impossible
to align properly. With some strength I was able to get it in place
and tighten it. Then a few months later the manifold cracked due to
the stress on it. The proper way to install it seems to be to go ahead
and tighten the manifold to catalytic convertor connection but leave the
other end of the convertor free and then install the manifold. Then
the rest of the pipe can be connected to the convertor (it's not easy
but there is enough room to get two 1/2 inch wrenches in there.) If
you don't have a catalytic convertor perhaps there is some other place
where the pipe seperates easily.
In general, I've discovered that the philosophy to use in installing
the exhaust system is to tighten it from the front to the back. Start
at the front leaving all the rear connections loose and work your way
back. That way there is no stress placed on any part of the system.
Since the engine is free to rotate quite a bit on its rubber mounts
and the exhaust is fixed to the chassis at several points, any stress
on the exhaust system leads quickly to cracks. This is also a good
reason to keep your engine tuned and running smoothly. If it misses
often at low idle then your exhaust is being flexed with each
shudder of the engine. This is probably why they installed all the
rubber hangers to support the pipe.
ron@vicorp.com or uunet!vicorp!ron
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