OK, OK, sorry to cause such a fuss, but I found what I'm looking for. What I was asking is what particular mechanical damage does the knocking and detonation incur to the engine?
Like this kind of stuff:
Detonation causes three types of failure:
1. Mechanical damage (broken ring lands, rod bearing failure)
2. Abrasion (pitting of the piston crown)
3. Overheating (scuffed piston skirts due to excess heat input or high coolant temperatures)
but they also said
One thing to understand is that detonation is not necessarily destructive. Many engines run under light levels of detonation, even moderate levels. Some engines can sustain very long periods of heavy detonation without incurring any damage. If you've driven a car that has a lot of spark advance on the freeway, you'll hear it pinging. It can run that way for thousands and thousands of miles. It's not an optimum situation but it is not a guaranteed instant failure.