[Shotimes] Knock, knock .. who's there?

[Adam Parrott]

Just a wee update for everyone.

The car is sitting in Tony's garage right now, near naked down to the bone.
Both the top and bottom-ends of the engine have been stripped down to the
heads, but the cause of the sound has yet to be found.  According to Tony,
there were no ejected shims (everything was intact and in spec), the chains
and tensioners look good, the cams are undamaged, there were no spun
bearings (thank God) and everything *seems* to be kosher.  In Tony's words,
the engine looks perfect and the rod bearings were "beautiful".

The new question is, WTF is going on here?  With nearly every aspect of the
rotating assembly in perfect or near-perfect health, what else could be
suspect, keeping in mind the loudness and intonation of the sound that is
being produced (see link in the message below for a copy of the clip that I
posted earlier)?  With shims, valves and rod bearings out of the equation
now, does anyone else have some ideas of where we might look in locating
this sound?  Tony and I both are really scratching our heads on this one.

All ideas are welcome and appreciated.

Adam

----- Original Message ----- 
From: "Adam Parrott" <parrotta@usa.net>
To: <shotimes@autox.team.net>; <TechSHO@topica.com>
Sent: Saturday, May 08, 2004 4:01 AM
Subject: Audio clip of knock (was: Knocking help needed)


To further aid those who are helping to diagnosis my aforementioned
knocking sound, I recorded a sample of it tonight and uploaded it to the
link below.  The file is about 602kb and approximately 50 seconds long.

http://hosting.superhighoutput.com/axianator/audio/sho_knock.mp3

For the first 30 seconds, you'll hear the engine start and sit at idle
while the microphone is held right above hood level and at just outside the
driver's window.  The 15 seconds after that hear the mic taken down to near
ground level while I give the engine two quick revs.  For the last 5
seconds, the mic is taken back up to hood level and the engine is shut off.

All recording was done by me, sitting in the driver's seat and holding the
mic just outside the drivers window.  The hood was also closed during this
recording, if that's any indication as to the loudness of the noise.

At some point this weekend, I hope to rule out the accessories as the
source of the noise by briefly running the engine with no accessory belt.
If the noise is still present after that test, then I'll try to get ahold
of a stethoscope and check the engine over and see if I can't better locate
the source of the knock.  I just pray that it's not an internal problem,
eg. rod bearings (only 9k old) or a thrown shim..

As always, all ideas and thoughts are welcome.

Adam