aligning the exhaust

[treed2 at wsu.edu (T. Reed)]

> A stock 16V midpipe doesn't require axle modification, or being banged
> on with a BMFH ;), you just need to situate the muffler and hangers
> properly.
>
> It was fine before you installed the new muffler, right?

Well.. not really.

Here's a timeline of events:
1) old muffler : rattled like crazy (internally, not on axle beam) because
   muffler was flaking off rust, had gaping holes and was on its deathbed.
2) new muffler : did not rattle at all, for at least a year or two
3) the handlebar-shaped 3/8" steel rod I made fell out somehow and the
   muffler started banging on the axle like crazy
4) I replaced the rod and put cotter pins in the end this time, the
   banging stops
5) About a month later, the rattling returns. Gradually gets more
   noticable. The hanger is still in place, and the exhaust does not
   appear to contact the body with the car off.
6) I've been putting up with it ever since.

> If the midpipe is hitting the body, locate where, it's usually shiny
> where it's been rubbing against, and adjust the muffler/hangers and

I've got a shiny spot on the body heat shield right above the axle beam,
but it's been there since the new muffler.

Okay, sort-of a new but related problem follows:

> midpipe away from it. With all the clamps loose, I twist the midpipe
                             ^^^^^^^^^^^^^^^^^^^^
			Any tips for accomplishing this feat?

It seems I overtightened the clamp on the muffler inlet. :P

I had to put a C-shaped shim inside the muffler inlet pipe in order to fit
the 2 1/8" stock midpipe to the 2 1/4" muffler inlet.

------------
        ----  <---shim
        ---------------

muffler                    to
inlet                      engine ->

        ---------------
        ----
------------

I think I cinched the clamp down too tight because I wanted to make sure
the muffler wasn't coming off. I didn't get it gorilla-tight, just tight
enough to (admittedly, a bad idea) lightly crimp things to the status-quo.

The (new, factory-stainless type) clamp comes off no problem, but the
pipes are stuck together.

When I adjusted the midpipe, I wound up just having to leave the muffler
attached where it was. So it sits all diagonal under the car right now
(I'm embarassed to admit it) .. but there's plenty of room down there and
its not contacting anything. So its more of a 'cosmetic' issue, I guess.
(oh, how can I be so vain?!?!! :) Wanting a muffler that sits level..)

> where I want it, and then crank down on the clamp on the cat, and then
> adjust the muffler/hangers.
>
> It's not the muffler, or heatshield rattling is it?

Not the muffler; wayyy too loud to be the muffler. If you're outside the
car (or you have the windows down) it sounds like one of those ancient
fire alarms they have at crummy public schools - the bowl-shaped bell with
the little vibrating mallet that hits it. My best attempt at transliteration:
`ring-dd-ringdlyling-gding-ggging-ring-dd-ling'

The heat shield is too foil-y to make that noise; it's got to be the axle
beam or something very very solid hitting the exhaust. It's such a 'bell'
sound.

And like I said it happens around 1100 rpm, but I think there are higher
harmonics as well - I haven't had my window rolled down while driving to
check (too cold outside!)

It can't be related to engine rocking, I guess, because it happens while
stationary at idle.

> Peter

Thanks!

-Toby