[Shotimes] Knocking update (kinda long)

[Adam Parrott]

Many thanks to everyone for the additional ideas and suggestions.
Unfortunately, I talked with Tony again tonight to get an update on his
post-weekend progress and things weren't sounding too good.

He told me that, even after replacing my apparently-good cam chain
tensioners with known working units from a junkyard motor and buttoning
everything back up for an idle test, the sound was still present in all
it's ugly glory.  He's also convinced that the sound is internal, being
loudest at the TB and fuel area near the 2/3 or 5/6 cylinders.

To help answer some of the recently made points and to give everyone a
quick refresher, here's a brief-run down of what Tony has done so far:

- Top-end tear down and inspection, including
  Complete valve gap check - all gaps within spec
  Cams, cam lobes, chains, and tensioners look great
  Tensionsers were replaced with good junkyard units, "just in case"
  All valves appeared to work properly during his "crank turning" tests
  No evidence of any foreign debris in any of the cylinders

- Bottom-end tear down and inspection, including
  Inspection of all rod bearings and related components
  All 6 rod bearings sets were intact, undamaged and like new
  No spun bearings or other metallic debris found in bottom-end

Tony says that the noise is too loud to be coming from the intake alone,
but he unplugged the secondary actuator during the idle test just to make
sure that the plates weren't bumping against the stops, like Jim Leyden
suggested.  Unfornately, there was no change in the sound.  He also said
that when the car was cranked via the starter alone (with no spark from the
DIS or fuel from the fuel pump - both were disconnected) that the sound was
not present - it only shows up when spark and fuel are applied and while
the engine is running.  My initial testing confirms this as well.

The flywheel and/or torque converter have not been fully checked yet,
however the flywheel *appears* to be fine aside from a few missing teeth.
To Mike and others who mentioned a possible cracked flywheel:  what *are*
the chances that an ATX SHO flywheel could have cracked?  Could this really
be the source of the sound as evidenced by the clip I posted earlier?

At this point, Tony thinks that the wrist pins are to blame.  I'm starting
to think so as well, and would be more inclined to buy into the theory if
it wasn't for what Jim (Leyden) said about them (how that they don't
usually go bad all of the sudden and usually change in intonation, etc).
Does the sound clip I posted sound like wrist pins to anyone else?  I've
never heard an example of V6 SHO wrist pin failure before, nor did I think
that it was a "common" issue like rod bearings seem to be.

At this point, Tony has done all he can without digging in further.  If the
problem does turn out to be wrist pins, I'll be pretty pissed.  My baby has
always been a stronger runner for an ATX, and I've always made it a point
to keep her well-maintained.  The engine has been commented on by Scott
Patterson, Tony and others as looking/being very healthy and the car
(overall) has given me few problems during my 2-year ownership.  Now that I
may be looking at an engine rebuild, I'm not sure what to do ..

FWIW, I'm heading over to Tony's house tomorrow afternoon to talk with him
and have my first look at the car since it was buttoned up.  I'm still
hoping that there's something small somewhere that he missed; however,
knowing Tony like I do, I don't think that will be the case ..  :(

Adam