I found this article while searching about "modern diesel engine blow-by".

From my experience, spot on in describing early engine break-in, causes & effects.

TheDieselStop.Com - www.thedieselstop.com

 

Good post and a good read

 

Great article. I have always preached running the Ford break in procedures and then go take the longest steepest grades pulling the heavist load you can find. Run it, run it hard and long.

The article refers to the keystone ring. The 6.4 uses this for the top ring. It is designed to expand with the heat and the amount of boost this motor provides..that helps to create the required seal.

Does the 6.7 employ that same type of technology?

 

Yup. All the diesels I owned were broken in with loads behind them. None of them had any problems with ring sealing.
Guys that baby their new diesels seem to have some issues with sealing.