A4 back on the road : Electrode damage in cylinders

[SuffolkD at aol.com]

I'll take a guess.  Is the spark plug electrode moving from cylinder to 
cylinder all through the exhaust valves?
I'd suspect the larger valve would be the way in, but say the metals too 
heavy for ejection by exhaust gasses thru the valve unless the Rpm's are right 
(increased airflow) and the part profile is prependicular to the velocity of the 
expelled gasses.

Therefore, it could be expelled from a cylinder at higher RPM only to "fall" 
back in (the next cylinder) under upshifting or closed/partial throttle.

If this is the path, would missing electrodes also be found in the CAT?
-curious Scott by BOSTON

In a message dated 11/21/2003 11:17:41 PM Eastern Standard Time, 
quattro-request at audifans.com writes:
> > I don't understand how a particle could migrate from one cylinder to
> > another.  Can anyone explain?
> 
> No.  But it happens.
> 
> The usual object seems to be a ring of pretty tough material, about 6mm in 
> diameter.  I've
> only ever found small pieces of debris nestling in the bores above the top 
> piston ring.  I've
> seen four engines in which one piece of debris has obviously migrated 
>