[s-cars] S6 pinging woes - the continuation

[Brett Dikeman]

On Tue, Jul 28, 2009 at 7:23 AM, Bares,
Vittorio<Vittorio.Bares at nuance.com> wrote:
> So what actually causes that nasty 'pa-ping' sound - is that metal on
> metal somewhere?
>
> If there is pre-ignition or detonation, both of which I believe result
> in the same condition, which is a pre-mature explosion or increase in
> pressure in the cylinder which pushes down on the piston while its still
> in the up-stroke part of its cycle?

Pre-ignition does not increase cylinder pressures and temperatures
much beyond normal values (I think).  Pre-ignition is bad because it
puts more force on the engine internals, and in ways it wasn't
designed...for example, if power is developed at exactly TDC, all the
force goes against the rod, crank, bearings, and head gasket/bolts,
instead of applying torque on the crank.  Detonation does increase
pressure and temperature, massively- it melts and bends things.

Cody's recommendation to drain/filter the oil and check the engine oil
filter are sound.

Brett