[s-cars] Lets get Dave a new motor, was: S-car Head Repair

[Tom Mullane]

You are right, we may never know what actually happened.  I thought Dave
said that, when reassembled, the car ran rough.  But according to Bill
Peron, the Parts guys told him that the car was never started.  I am
inclined to believe the former; I'm sure they discovered the problem
when the car was started.

I imagine that they were holding the engine somehow while trying to
loosen the bolt, and the engine turned suddenly.

Tom

-----Original Message-----
From: serge [mailto:serge411 at speakeasy.org]
Sent: Wednesday, December 18, 2002 3:54 PM
To: Tom Mullane; s-car-list at audifans.com
Subject: Re: [s-cars] Lets get Dave a new motor, was: S-car Head Repair

I was under the impression that they ran the engine out of time, but if
they
timed it correctly it would explain why only two valves were bent.
Still,
enough force to bend two valves, and using a piston to do it, that must
have
been a big monkey/ big bar combo.


Serge Filanovsky

95 S6 Avant





> Serge,
>
> According to the dealer's account of what happened, the valves were
bent
> when the crank bolt was being removed, with the belt off.  When the
belt is
> off, the cam does not turn; the cam must turn for more than two valves
to
> contact the pistons, regardless of how far the crank is turned.
>
> Finally, the bolt was removed, the belt changed, and the engine
started.
> Assuming that the belt was put back on properly, there would have been
no
> further piston/valve contact except possibly some additional contact
between
> the two bent (and now possibly stuck part way open) valves.  But even
the
> valves that where bent during the crank bolt removal should not be
able to
> cause significant damage to the pistons at this point; with the cam
back in
> time, there would be nothing holding them open from the cam end.
Piston
> contact would just push then shut.
>
> My contention would be that the valves where not bent by the force of
the
> engine running, but by the monkey lad with the big bar.  IME, damage
to the
> piston *should* not be much more that a "clean spot " or small nick.
I
> would not recommend rebuilding an otherwise good running engine for
such
> minor damage.
>
> The truth is, without actually seeing the damage, we can only
speculate.
> But I have replaced valves on cars that have seen broken belts, and I
have
> seen few pistons that gave me any reason to do more than change a few
> valves.  Think about how the damage occurred; it would have been a
totally
> different situation if the belt let go on the interstate.
>
> Tom
>