Checking for Cancer....was: RE: [Shotimes] Ticking/oil leak

[Kerry Kinion]

Don't want to take the belts off - I just got the F*$@#rs back on.  I
still hope to hook up with Josh S. soon - If he can't tell me what the
sound is then I'll tear the belts off.  As I told Josh, the most recent
is this:

I listened to it a little more today and I think it's something going on
with Cyl #6.  Symptoms are as follows:

1. When I listen thru the stethoscope - the main place I hear the noise
is thru the valve cover bolt near Cyl #6.

2. Noise only happens with acceleration - not on deceleration or at
idle.  Starts at about 2400 RPM's.

3. Seems to have creeped up a little bit to where I can hear it above
3000 RPM's to about 3500 RPM's.

Kerry

-----Original Message-----
From: George Fourchy [mailto:krazgeo@jps.net] 
Sent: Thursday, April 24, 2003 4:17 PM
To: shotimes@autox.team.net
Subject: RE: Checking for Cancer....was: RE: [Shotimes] Ticking/oil leak

On Wed, 23 Apr 2003 23:35:39 -0700, Kerry Kinion wrote:

>And by the way - If it was crank cancer
>would it be heard thru the entire RPM range?  If a valve shim is out of
>spec would it be heard thru the entire RPM range?  Question is: why
only
>between about 2400-3000 am I hearing this??

We can't answer the question why you are hearing the noise only between
2400-3000
rpm until we find what the problem is.  Have you tried running the
engine with both
accessory belts off, to silence all the external accessory sound
sources?  I did
that when diagnosing my engine, and it still made the sound with all
accessories and
pulleys stopped.  All you have to do is start it, and run the revs up
and down a
couple of times.  It won't hurt it to run it without the waterpump for a
minute or
less, but make sure it is at least partway warmed up.

The classic crank cancer symptom is noise at idle to about 2500 rpm
after the engine
warms up.  The noise comes from the loose crank sprocket slamming back
and forth
against the key (and ringing the crank like a big bell) due to the
tension on it
from the various cam lobes varying the effort required to turn the cams.
Above
about 2500 rpm, momentum of the cams evens out the load, and this fact
combined with
the fact that at that speed and above there isn't time for the sprocket
to bounce
back and forth stops the noise.  Until I took my engine down to find
this looseness,
there was no way I could figure out why such a noise would be there, and
why it
would be so loud and heavy.  The instant I saw the gear and key, I
understood.  With
the miles, I thought it might be a rod bearing, although that noise gets
worse with
revs, and my engine quieted down.  I have heard an engine with a
definitely bad rod
bearing, and there is no doubt about it....it sounds like it wants to
come apart, in
all directions, right now. 

I can't say I've ever heard a valve shim noise in a SHO engine.  The
Lowrider had
one valve that was .002 looser than specified after 201k miles, and that
one was
basically inaudible.....all its noises have been from noisy idler
bearings and that
crank cancer.  I'd say that the sound should be fairly clicky, rather
than hammery,
since the physical size of the parts we are talking about is very small,
similar to
a valve tappet sound from an older V-8 with a collapsed lifter.

Let us know what it sounds like without the belts.

George
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