Just my educated guess, the piston crowns and heads of the 6.4 will have a ceramic coating called mullite.
This coating allows extreme combustion temps without the metal reaching high temps because it becomes very very hot, but doesnt transmit the heat on to the steel beneath it.
This mullite is the latest version of when they were experimenting with ceramic pistons and heads.
dont even ask how i know this, its just an educated guess

 

Is this process used elsewhere? Interesting.

 

This process has been under development for years by cat and cummins and one other company i cant remember, it was a semi engine manufacturer though.

These ceramic coatings glow red hot while running and cause extremely great results in terms of HP, tourque, and doing so with cooler engine temps.

The only problem is getting the ceramic coating to adhere properly. The last i heard, the coating adhesive would never make it past 50,000 miles of run time.

I read all this one early sleepless morning after somebody was telling me about an entire diesel engine moulded out of ceramics designed to run super hot, and i got side-tracked.

 

The owner of a local dealership confirmed this to me today. Did not reveal anything else. Just thought I would let you know.

 

Well, whatever to make more power and be more reliable.