picaza > wrote:

>can anyone compare/contrast ping and knock?

Actually, ping is a common term to indicate what is officially knock.
It sounds much more like "knock" to me than as "ping," but anyway.

However, the engine people refer to wild ping when the mixture is
ignited at the wrong time and place by surface deposits. It is
characterized by one or more erratic sharp cracks. It is a
heart stopping sound for the loving Miata owner, I can tell you.

> also, does one get more ping if the timing is more advanced
>or more retarded?

Depends. Normally retarding timing reduces knock. However, retarding
timing by 340 degrees may have an opposite effect.

In addition, a kind of knock caused by ignition by hot surface
deposits is not controllable by reducing spark ignition advance.
(If the surface deposits are really, really hot, I assume.
Otherwise reducing advance would surely help, I would think.)

Leon

--
Leon van Dommelen Bozo, the White 96 Sebring Miata .)
http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)