loud motor = happy motor?

[Gary Derian]

Revving an engine out of gear will show max advance.  You will have full
centrifugal and vacuum advance.  Flame fronts do not collide as you
describe, the end gas detonates and creates a shock wave.  Modern Chevys run
best at 32 to 34 degrees.
Gary Derian <gderian at cybergate.net>
>  >>

snip
>Well, to be truthful, you will never see full advance curves on a motor
revved
>out of gear. You simply cannot achieve any sort of vacuum to run the
advance,
>so in reality, you are revving the motor with retarded timing. Ignition
timing
>is a factor dictated by today's gasoline.
snip
. If the ignition timing is too far advanced,
>(farther before TDC), the maximum flame front will occur too early, and the
>piston will actually fight the flame front on it's travel upward, causing a
>pressure spike, and that pressure causing the actual secondary ignition
(and
>flame front) of the remaining fuel. As the two flame fronts meet in the
>cylinder, a harmonic clashing occurs (audible ping), and instead of the one
>flame front propagating throughout the cylinder, and creating power, both
>flame fronts collapse, and power diminishes, along with the real
possibility
>of extensive engine damage!
>You must also keep in mind that all engines are different. For example, a
>stock Chevy small block will run with a static timing of 4 deg. advance,
and a
>total of 40 to 44 deg advance at full power. A Pontiac engine, on the other
>hand, runs with a static timing of 12 to 16 degrees, and 36 to 38 deg of
>advance at full power. Also keep in mind that if you change an engine's
>combination of parts (a new cam, heads, etc.) the ignition timing demands
will
>change. Other things that will change an engine's demand for more or less
>timing is ambient air temp. and density, altitude, humidity, gas quality,
load
>(towing, etc.), and state of tune.
>Hope this answers your question!
>PMDRACER at aol.com