[ihc] RE: Kyle's bits

["Jim Grammer" <jgrammer@xxxxxxxxxx>]

IME, worn cam lobes don't cause anything I'd describe as a 'knock'. If it's
bad enough that the lifter can't maintain 0 lash, the lifter will make a
'ticking' sound as it floats free between the cam base circle and lifter.

Until I peeked at the pics, I was going to suggest piston slap. Typically
loudest at idle, going away(mostly) under load, isolate by pulling plug
wires and using a stethoscope. Rod bearings are kinda the opposite,
generally quiet at idle/louder under load.

Your stock oil pressure gauge is basically useless other than an indicator
that the oil pressure went down *some*. It won't tell you how much, or where
you started. A high quality mechanical gauge is needed to determine your
true oil pressure, I use  an commercial unit that I just screw into the side
of the block. The critical reading on an IH SV is hot idle oil
pressure(totally warmed up, like 20 min. of idling). I have not seen any IH
SV that had decent hot idle pressure fail to have enough oil pressure at
higher RPM.

That said, the bits in your pics look like main bearing material to me,
possibly rods. BIG chunks, muy malo :( There aren't any shims in the bottom
end. Cam bearings(most prevalent cause of low oil pressure) generally show
up in flakes, not big chunks, and have a central oiling groove. Hate to say
it, but something inside your motor is *really* unhappy.

As long as the pan's off, pull the main bearing caps one by one and check
the bearings. If you don't see anything out of the ordinary, do the same
with the rod caps.

Jim

Date: Thu, 20 May 2004 21:23:25 -0700
From: Eighteen Rabbit <thor7358@domain.elided>
Subject: [ihc] 266 w/ knock -- forensics help requested!

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?