[ihc] 266 w/ knock -- forensics help requested!

[Eighteen Rabbit <thor7358@xxxxxxxxxx>]

IHers,

     The left bank of the 266 in my Scout 800 has been knocking since I
purchased it a couple years ago.  I was told the sound was probably a worn
cam lobe, and I didn't worry about it too much because the oil gauge read
right in the middle at road speeds.  (Well, I worried, but I still drove the
truck.)  It still sounds about the same, but after I watched the oil
pressure drop on a trip last spring, I have hardly touched it.  Hoffs
suggested I try running an extra quart of oil, so I tried that, but
everything ran the same as before.

     In the mean time, I have changed all the lifters and push rods on the
left bank.  I also installed a replacement rocker arm & rockers.  It still
knocked, so I changed out the water pump, thinking that could be the cause.
I performed the tests in the factory service manual to see if the sound was
from a loose piston pin or worn/loose rod bearing, but it passed those.  The
last thing I wanted to do is pull the cam shaft!

     As a final resort, I thought the oil pump could be going bad, so I
dropped the oil pan.  Much to my dismay, I found some metal in there!  I am
not sure how much of the small stuff I missed, but I salvaged some of the
bigger pieces.  It looks like it was in a strip, about 3/4" wide.  It is
non-magnetic and about as malleable as lead.  Maybe a shim or something?

     For those of you who have experience with engines, I have posted some
photos on the web for you to look at.  Hopefully you will recognize the
pieces!  http://www.uidaho.edu/~thor7358/IH/  Also, how likely is it that
the source of this debris is the source of my knocking?

Thanks,
     Kyle Thoreson