I just took my 2007 Cooper S to the dealer because of poor power. One of the things they mention is...
FOUND TO HAVE SUPERKNOCK FAULTS WITH FUEL
SHUT OFF, RECOMEND MANUAL VALVE CLEANING,
SPARKPLUGS, FLUSHES AND PROGRAMMING.
COMPRESSION IS EVEN @ 170PSI (SCAN FOR
FAULTS)
I've never heard of 'Superknock'.......anyone have any ideas or fixes?

 

Super Knock aka pinging. From what I've been told this is the official description for the carbon build up issue.

 

so do we know what is involved in 'Manual Valve cleaning'.
Does this mean taking the head off and valves out?

 

It's also called 'walnut cleaning'. Basically its sand(crushed walnut shells actually) blasting the valves and intake track. I do believe they pull the head to do this, but I could be wrong. Hence the crazy price 600-1200.

There have been a few who tried doing the manual cleaning themselves with tools and solvents.

 

Will the 2012 JCW have an issue with carbon buildup?

 

If the JCW has the older N16, it most likely will have carbon issues eventually. The 2013 JCW is supposed to get the newer N18 which is not to have the issue (or maybe not as bad...). That said, from forum discussions driving style plays a large influence, so does fuel choices... Its a crap shoot.