Re: quattro-digest V4 #782

[Joan Kotjarapoglus <jkot+@pitt.edu>]

Our first family Audi, a 5000 non turbo was given to our dauther on
graduation from college (two years ago).  For at least several years
prior, there is a valve tapping sound that comes on between 2400 -
3000rpm, none audible above or below, and not while  sitting in neutral 
and engine reved to 3000rpm.  If cruising down a flat highway, even under
light light load, you will hear the tapping sound.   
	I had always assumed it was an engine problem, but mechanics whose
opinion I respect though it was ehaust related.  Over 
time, I have replaced all of the mufflers and cat.  Even had the exhaust
manifold pulled, machined flat and broken studs replaced.  The noise
still remains.  It is even more evident now that I hav replaced one of
the noisy mufflers.  Car otherwise runs fine and has about 120k miles on
engine.  Checked compression and all cylinders where within same range
and comparable to my 1985 with a rebuilt head purchased from audi.
	Does anyone have an wisdom to impart on the source of problem -
lifters - valve guides - floating valve????    HELP
    George Kotjarapoglus   jkot@pitt.edu
	,