Re: One valve down. Is it safe to drive ? (for a while ...).

[zm@mhcnet.att.com (Zafer Mehmood [209])]

> 	For those of you that asked, here is the compression test after the
> belt was installed (sorry, I have no previous measurement).
> 
> 	0 - 75 - 65 - 70 - 35
> 
> I think thats _low_ isn 't it ?

Yes. Something is wrong here; like improperly installed timing belt??
If I remember correctly, the compression spec for these cars is somewhere
like 130 or 150 psi. I can see how one cylinder would be down to zero
if you have a valve stuck open. But all of them low implies all bent valves
(in which case it would be hard to believe it runs) or timing is off.
I suggest you take the car to another audi mechanic or dealer and have
them take off the timing belt cover and check if the timing marks line up.

> The car right now is in "Kars", and the mechanic without having seen it, insists
> that an '86 5K T, shouldn't damage valves, therefore he will have it running
> today. Please join me in my prayers ...
> 

The 5000 turbos definitely can damage valves; its the non-turbo ones
that are probably free-wheeling.

> This Just In:
> 
> as I was writing the mail, the mechanic called.
> He says I have a cracked head or a burned valve.
> He hasn't taken it apart yet to see exactly what is it. (the car was fine before
> the belt insident, no rough idling, or any signs of major damage ...).
> If it is a valve I am looking at about 550 parts+labor, if it s a head 580
> 

If this is the same mechanic who replaced the belt, get the car away from
him (see above). If you really trust him, have him reconfirm that the
belt is indeed installed right. It is possible that a cracked head could
cause the low compression readings, but it is unlikely that the head would
crack due to a timing belt breaking.


-----------------------------------------------------------------
Zafer Mehmood				   AT&T Bell Laboratories
zm@mhcnet.att.com			   Murray Hill, NJ