I received quite a bit of comments/interest over the Holiday.   Two questions overlapped with detonation damage to a head gasket and pre-ignition.  Since these are similar in nature, I will give a broad analysis and please email me at: kpapajohn@usasealants.com for further insight. 

Q.  Is detonation causing problems with my head gasket?

A.  Detonation is damaging for several reasons. One occurs with high levels of compression resulting from accumulation of carbon in the combustion chamber.  This is mainly found in late-model engines which require premium octane fuel.  (Which gets to my second question).  Compression can peak and the fuel will randomly ignite prior to a spark setting it off.  This will cause the engine to knock and ping under the load. 

You may measure the head gasket with a micrometer in the area where it failed (be careful) to see if overheating (detonation) was the problem with the head gasket failure.  If you notice the (crushed) gasket measures thinner in that hot spot failure along with the combustion chamber's cracked armor then detonation damaged the head gasket.