Ford's answers to the NHTSA 6.7 Investigation
There was a request for a link to Ford's answer's to the NHTSA investigation posted on a previous thread, since closed. Here is the link: Ford's NHTSA Answers to the 6.7 investigation This PDF i...
Forum Discussion
BenK wrote:
Now noodling why H2O is such a bugga-boo
Cavitation to create a vacuum to vaporize H2O isn't as bad as an air bubble
The air bubble (micro) does ripe off molecules, but vaporizing H2O isn't as
aggressive, or am I wrong?
I need to consult an expert on this, but I can already guess the answer, "it depends" on what is in the H2O. What does H2O have in solution? Ethanol? Methanol? Iron Oxides? Calcium? etc.
There must be something else that interacts with that vaporization event(s)
Part of that witches brew (organic amines) ?
Another new thought based on NewsW's comment of high expense of DLC and to drive
selectively plating areas to leave other areas not plated.
Is there an interaction with the H2O vaporization on the non-plated surfaces?
See above.
What is/are the non-plated surfaces? Iron/steel/plastic/SS/etc ?
Maybe that then cause debris to then have either or both the cam/follower and
piston/cylinder collide with that debris to then scrape off DLC and/or
interference to gouge ???
Based on the look at the design from CP3 to CP4, they went from 2 to 1 stage, therefore, pressure, ceteris paribus, have to be higher at the piston / cam section.
Wait!
They jacked up the maximum pressure from 1,600 to 2,000 bar, an increase of 25%!
That is before any changes in temperature depending on whether there is more or less cooling of the fuel.
What that says is something that is not a problem in CP3 can become one.
Even if the coating stayed identical.
That would explain why the coating might have passed durability tests in CP3, and was retested at CP4 pressures and temps, and it all passed with reference fuel, but fails in real life fuel.
