[V8] Simple TB Change

Buchholz, Steven Steven.Buchholz at kla-tencor.com
Fri Oct 7 21:29:43 EDT 2005

... assuming that you are using the cam locks and following the
procedure you guarantee that the crank to cam timing is set within the
limits of the tooling used when you loosen the cam pulleys ... that is
exactly why the factory specified procedure is the way it is.  If you
don't have the cam locks I would wholeheartedly support the statements
that loosening the cam pulleys is a very bad thing ... 

With the old Audis there are timing reference marks on the cam pulleys
that you use to establish the crank/cam reference ... the PT engine does
not have such marks.  The big concern about doing the job with the
pulleys snugged up is that if there is some slop in the belt you may
very well set the engine up with a tooth or more of error ... and
there's no way you'd be able to tell that it was the case.  I agree that
the belt is designed not to stretch significantly, and belt stretch has
little to nothing to do with the procedure being the way it is.  There's
no doubt ... other methods can be devised that allow the belt to be
replaced without loosening the cam pulleys ... and if you're careful and
know what you're doing they will work.  Using the factory procedure
eliminates the need for those prior caveats ... 

Steve B
San Jose, CA (USA)
> New belt has same number of teeth as old belt.  Would you change the
> relationship between the cams by a half notch, especially given that
the new
> belt will stretch just like the old one?  When I take off the old belt
> I put on 60+K miles ago the marks I put on the cam sprockets and the
> remain quite the same.  To me, the danger of loosening the sprockets
> getting them wrong is far more dangerous than being a fraction of a
> off.  270K miles of reliability and economy did not prove me wrong.

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