Good one :D.

Pinging, knocking, dieseling (which is precisely what it is) - all detonation - when ya don' want it!

Pinging and Knocking can be the same things, but not always, rod knock is different.

Dieseling is 'run-on' after the ignition is turned off.

Any kind of knock, be it rod or ignition, is bad, BAD, BAD!

However, it is absolutely crucial that one distinguish between "knock", which is always bad, and "knockers", which, with the exception of old, worn knockers which have succumbed, over the years, to the inexorable pull of gravity and have become, in extreme cases, unrecognizable as knockers, are of utmost importance!

Cams are generally described in terms of "lift". When dealing with knockers, "uplift" is the desireable characteristic to be sought after (most often lacking in older models unless silicone restoration has been done).

Regardless of age, properly maintained knockers are a joy to behold and can still easily arouse one's passion. While silicone restored knockers may be percieved to be disengenuous to the purist, lubrication is the secret to maintaining the similarity between the old and the new - the old retain their lubrication nipples (so, I'm not just offering "lip service" here!) and to the casual, impassioned observer, they suffice as well as newer, e.g. 18 yr. old, knockers do.