scary engine/clutch noise-- wth??

[treed2 at u.washington.edu (T. Reed)]

I'm not sure where to begin.. for the past 2 or 3 weeks i have had a bit
of a quiet rattle type noise when I step on the clutch pedal. It only
happened sometimes and it seemed to me (at the time) to be related to
what angle the car was parked at relative to the ground, so I thought
nothing of it -- I figured it was a wire or power steering hose being
lifted up by the clutch lever on the tranny and banging on the
firewall or a heat shield from the engine vibration. In retrospect, that
sounds like a stupid explanation, but I didn't have helper present to
step on the clutch while I listened, and since the noise only happened
sometimes I did not think it was that important to diagnose. "Just another
rattle"

Anyhoo, my troubles began when I went out to my car 2 days ago and started
it up. I immediately shut it off because the engine did NOT sound normal
at all, and it had a loud BANG BANG BANG metal-on-metal type of noise. I
thought for sure I had broken a timing belt. Trying not to crap my pants,
I calmly took off the timing belt cover.. but my timing belt was fine. I
checked the oil and it was a little low but there was plenty of it and I
could tell there was oil getting to the bottom valve cover because the oil
cap was dripping when I removed it.

So I thought maybe my exhaust broke and the loud noise just startled me--
after all I had only listened for a second before shutting the motor off.
I started it again for a few seconds and listened. I decided that if it
was exhaust noise, then that was only part of it. It sounded like metal
hitting metal in at least one cylinder, and the valvetrain sounded like it
was bone dry of oil. clack-clack-clack. Again, these are just my thoughts
at the time based on the sounds. It was so loud I could not trace it to
any particular area (back of motor/exhaust/tranny/etc)

I sat there staring at it for a while and churning over in my head what
could have happened.. maybe the starter solenoid was binding and the gear
was half-way engaged with the flywheel.. maybe a bolt somehow got in my
intake and was getting mashed by a piston. No way to know ..

I decided the next step was to pull the coil wire. Since the damage was
"already done" from me starting the motor I turned it over with the
starter a few times. I could hear the normal gibbity-gibbity-gibbity
starter noise but it was more of a 
gibbity-gibbity-bang-gibbity-gibbity-bang. It did not sound good..

I stood there and thought some more then I hooked up the coil wire again
and tried to start it again. I heard the bang noise once, then suddenly
everything was back to normal. The idle was rock solid, the only noise was
the smooth bmmmmmmmmm tone of the exhaust. Lifters quiet, no 
metal-on-metal noise.

What the hell!?! I killed it and started it again-- still no sign that
there was ever a problem. I took the car for a drive and it was absolutely
normal. The only thing I noticed was that the quiet rattling noise was
still present when I pushed in on the clutch pedal.

I haven't driven the car since and I haven't touched it either. I've been
trying to think of what could be wrong with it. My intuition tells me it
is a clutch problem of some sort. A couple of backed out flywheel bolts? A
canadian-made sachs pressure plate? The skeleton of a small animal that
crawled inside my bellhousing somehow?

I don't know what to think, so I'm asking for your help, list. It's
raining and I don't have a garage so I'm still indoors brewing it over.

Here's the relevant info
87 16v Scirocco
2l 16v installed last september-not rebuilt; just bolted up
new sachs clutch disc installed w/spline grease 2 years ago
new sachs pressure plate 2 years ago
new sachs thrust plate and retaining ring 2 years ago
new pressure plate bolts and flywheel bolts last sept
blue loctite already on flywheel bolts when I bought them
new t/o bearing last sept
lightened flywheel last sept
stock agb tranny
new clutch cable 3 years ago
plastic timing hole cover installed
new bosch rebuilt starter last oct
new starter bushing last oct

I didn't pay enough attention when people here were talking about pressure
plate springs breaking, but it doesn't seem to me that my car would drive
just fine if that had happened. So I'm inclined to think that's not it.

I would greatly appreciate any help.

Thanks

-Toby