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

[Steven Stegmann <steve.stegmann@xxxxxxxxxxxxx>]

Kyle,

That strip of soft metal is a bearing insert. 
Guaranteed!  3/4 inch wide sounds like a cam bearing. 
Crank bearings are wider.  

When I rebuilt my engine a couple years ago, due to a
knock in the engine, I found the cam bearings eroded. 
They were still in place but the exposed surface was
worn away.  Never did find any identifiable metal in
the engine.  My knock was worn cam lobes which
prevented the lifters from smoothly following the cam
contours.

You need to tear that thing down and replace the cam
bearings and probably the cam too.  Have a machinist
check the cam bores to see if they are too damaged to
take new bearing inserts.  May need to align bore the
cam. Replace the cam and lifters as a set.  If the
ones you inserted show no wear then you can probably
use them.

The cam comes out the front of the engine but the rear
cam bearing comes out the back of the engine through a
hole closed by a simple plate behind the flywheel.

You also need to check the oil pump for metal damage. 
Most likely the filter stopped the metal from going
anywhere else.  

When you tear this thing down do **not** reuse the
connecting rod bolts.  They are tightened to yield
when installed and should not be reused.  They ain't
cheap, but if they fail...

Steve
--- Eighteen Rabbit <thor7358@domain.elided> wrote:
> 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