RE: Audi 100 typ 43: valve adjusting..

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

> I never did it before, as the correcting is by applying shims (on my
> previous car 
> I succesfully did adjusting 'screw-adjusting' (I don't recall the correct
> name for 
> it)..
> 
> Would you think it is possible to do it yourself?
> I do have a Haynes manual on this type of car, and comparable German 
> manuals, so the procedure should be clear..
> 
Yes, it is actually quite easy to replace the shims, at least this is true
for me when I use the two special tools that are for that purpose.  One tool
forces the buckets down and the other is like a pair of pliers except it is
designed to reach around the cam.  You will also need a set of calibrated
shims (I can't think of the proper name!) to measure the gap between the top
of the bucket/shim and the bottom of the cam when the valve is closed and a
micrometer to measure the nominal thickness of the shims in the buckets.
Finally, it is probably a good idea to find a place where you can get the
shims for the buckets.  Here in the USA most Auto Parts Stores carry them
... at least they used to before everyone went to hydraulic lifters!

The first step of the process is to measure the gaps on all valves against
the spec ... engine cold.  If a particular valve is in the spec range you
don't need to do anything further.  Remember that as the engine wears the
gap tends to get smaller, so if you are picky you might want to re-shim any
valves that are close to the minimum limit if you have other valves you'll
be doing.  Once you've decided which valves need to be re-shimmed and how
much difference you plan to apply for each valve you can start removing the
shims.  After removing each shim measure its thickness with the micrometer
(most shims already have the nominal thickness printed on them, but they can
wear), write the measured thickness on the shim, subtract (or add) the
necessary amount to bring the gap back to spec and write this value down for
this valve.  Once you have done all the valves that need to be adjusted,
make a list of the new thicknesses that you need and see how many of them
you have from the shims you took out (remember that there is an acceptable
range for the gap!).  If any sizes remain over you'll need to purchase them
...

Installing the shims is pretty easy ... compress the bucket down and slide
them in.

> Would it be wise to let 'adjustment: yes or no' depend on the compression
> rate 
> of the engine?? I do have a compression tester, so if readings are within
> limits 
> indicated in the manuals: is adjustment needed then?????
> 
I've actually never heard of this.  I suppose that there will be some effect
on the compression due to the improper gapping of the bucket ... but rings
can also contribute as well as other things.  If you're concerned about the
valve adjustment, go buy yourself a valve cover gasket and measure the gaps
... it isn't that difficult.  If you find that they're all close, you're
done.  If any need to be changed you can do them yourself or choose to have
someone else change them for you ...

Have fun!
Steve Buchholz
San Jose, CA (USA)