[no subject]

["Jim Grammer" <jgrammer@xxxxxxxxxx>]

>Date: Thu, 20 May 2004 23:11:12 -0700
>From: Eighteen Rabbit <thor7358@domain.elided>
>Subject: [ihc] Re: 266 w/ knock

>>>  did you ever use a stethoscope to try to
>>>  pinpoint the knock? It seems like you were
>>>  looking all over for it, so I'm wondering
>>>  just how definite you were on the source to
>>>  begin with.

>John,

>    Thanks for the response!  The sound is a "tick, tick, tick" that
>changes proportionately with RPMs, and does not change sounds due to load
or
>acceleration.  It is definitely, and without any doubts, coming from the
>left side when listening just by ear.

OK, a tick, not a knock ;) Ted's notion to check for an exhaust leak is a
good one that I often forget. You would be amazed how much a leak can sound
like valvetrain noise.

That said, you have the bearing chunk issue. I still *don't* think from the
pics that we're looking at cam bearing material. Since you have the pan off,
checking the main and rod bearings is another couple hours work. If you find
the culprit that way, you can prolly get by with replacing the affected
unit(s).

If I'm wrong, and/or(not mutually exclusive case)your cam bearings *are*
worn out, the resulting low pressure to the lifters will cause lifter noise
like I described even with new lifters. Many of us have BTDT. To test, use
the aformentioned accurate gauge and idle it till it's nice and hot. If the
pressure drops below 5PSI, there's not much you're going to be able to do
other than pull the motor and replace the cam bearings. 5-10PSI, you're in
questionable territory. IH published both 5PSI and 10PSI as minimum #'s at
various times. I had a 304 with 7PSI at hot idle that didn't make noise at
idle, but sang like crazy at 2500(was not a head drainback problem). Above
10PSI you're OK, generally.

The bad news is that you might find a messed up main/rod bearing, replace
it, and still have hosed cam bearings. At least you already have the pan
off...

Jim