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
Agree, it all points back to this area as the root cause
Have said using a cam instead of a crank is wrong for this type of PSI.
Again, mystified how the highly educated designers can deem okay to go to DLC
on a roller with this level of PSI.
That has sooooo many failure or potential failure issues just looking at it from
the outside. From the 'dent' the roller and cam 'will' have and made worse at
shutdown. Where the poor lube is squeezed out to then have a dry cold start, albeit
the PSI's won't be as high on the first rotation...till the piston develops 2,000 BAR
Again, DLC or diamond is the best known non-stick material known to mankind. How
does a very poor lube like diesel manage to both coat (film strength) and during
shutdown/over-nite keep a film on there to prevent dry starts?
ANY roller/cam miss-alignment will cause scuffing of material and maybe
that is yet another reason they went to DLC, but then an oxymoron, as the roller
needs some level of traction to start rolling. Otherwise it will skid
What is the cam rotational speeds, both RPM and SFPM? Is the follower spring
force high enough to prevent floating it off the cam?
Betcha on that, that the piston floats because I've not seen any spring pushing
it against the follower, nor positive capturing mechanism
A journal bearing would have been a better choice, but that won't work on a cam
and say look a any ICE's crank/rod bearing...but that would be more expensive...
Have said using a cam instead of a crank is wrong for this type of PSI.
Again, mystified how the highly educated designers can deem okay to go to DLC
on a roller with this level of PSI.
That has sooooo many failure or potential failure issues just looking at it from
the outside. From the 'dent' the roller and cam 'will' have and made worse at
shutdown. Where the poor lube is squeezed out to then have a dry cold start, albeit
the PSI's won't be as high on the first rotation...till the piston develops 2,000 BAR
Again, DLC or diamond is the best known non-stick material known to mankind. How
does a very poor lube like diesel manage to both coat (film strength) and during
shutdown/over-nite keep a film on there to prevent dry starts?
ANY roller/cam miss-alignment will cause scuffing of material and maybe
that is yet another reason they went to DLC, but then an oxymoron, as the roller
needs some level of traction to start rolling. Otherwise it will skid
What is the cam rotational speeds, both RPM and SFPM? Is the follower spring
force high enough to prevent floating it off the cam?
Betcha on that, that the piston floats because I've not seen any spring pushing
it against the follower, nor positive capturing mechanism
A journal bearing would have been a better choice, but that won't work on a cam
and say look a any ICE's crank/rod bearing...but that would be more expensive...
