Squealing Camshaft Bearing (long)

[Dr. Ian McArthur]

This is a multi-part message in MIME format.
--
[ Picked text/plain from multipart/alternative ]
I have a squeal in the front camshaft bearing in one of my 5TQs.  To make
sure of the problem I removed all of the belts for alternator, air and
hydraulic pump, removed timing belt cover and checked for the source of the
squeal with a stethoscope.

The squeal (at idle) seems to come from the front cam bearing.  I recently
repaired the head after a broken timing belt bent some valves.

I think the timing belt had been previously tightened way too much (not by
me!) as the crank sprocket and water pump teeth were badly worn and the
timing belt broke after far less than 50,000 km.

When I had the head dis-assembled I noted that the lower half of the front
cam bearing (the surface on the head itself) is scored.  The cap is not
scored.  This leads me to believe the timing belt was done up so tight it
caused the scoring, the tooth damage and the belt failure.

Now the question:  what to do?

Is there a possibility that the belt was so tight it was pulling the
camshaft down so hard that oil was not getting to the bearing surface?  I
have checked the oil passage in the head under the front bearing and the oil
return passage behind the camshaft front oil seal.

The advice I have from my local (very good) machinist is to use some fine
emery cloth (or whatever the really fine stuff is called) and dress the
bearing surface to remove the scoring.

I want to do something to cure the squeal.  It is both annoying and a
concern that I might suffer a catastrophic cam failure.

Any advise would be greatly appreciated.
************************************************
Dr. Ian McArthur, Consulting by Acronym, Cochrane, Alberta
sutul at telusplanet.net
--