[satinghostrider]

The issue here could be from a variety of reasons. Tune, low octane fuel, overheating (most likely factor IMHO seeing how the damage has spread). But one that draws the most interesting question is why an official BMW representative office was so confident nothing was wrong with my engine BUT they have to void engine warranty and gearbox warranty??

If they are so confident nothing was wrong with my car, what need is there to void the warranty? I mean I have never seen anything like this before. What ever has happened has happened and it cannot be undone. I have made my decision and have lived and accepted it. What I cannot accept is things like lying to me on the engine being perfectly fine when its not. Taking a go at voiding my gearbox warranty when they did a royal fuck up of changing the DCT gearbox oil and have found a convenient time to void that as well because they knew it was their mistake and it would come back to them if my gearbox broke down half way? I mean all this just doesnt add up. Also, they never ever offered me a solution out of this. I had to keep asking and demanding solutions to a point I showed them the finger and went my way.

As to what happened, I have been told that the spark plugs in the S65 do not have individual knock sensors. It uses the spark plugs itself to detect knocking in the engine. When my spark plug misfired, I did not get any error code. The reason why is because the the two prongs has melted against the centre stem and there was no way for an ECU to throw a code this way. The only way the ECU throws a code is when it detects there is no "arcing" of the spark plugs which can only happen if the two prongs are still away from the centre stem and not melted against it. So what basically happened could also be "pre-detonation" where the spark plug is red hot (Not arcing) and there was a pre-detonation. Meaning there is already combustion in the chamber even before the piston is on its way up. And the piston with the broken edges is the same chamber where my spark plug misfired. The tune I had on my car was just to remove the O2 CEL lights for my Akrapovic, top speed delimit and some decent power as we have reasonably good fuel here. I was careful not to overdo the tune as this engine makes more than 100hp per litre and it would be purely stupid to ask the block for much more. If any, it only accelerated the weakness on my engine. I think it would have happened to my car sooner or later even if it was stock to the virgin.