Ford's answers to the NHTSA 6.7 Investigation

NewsW wrote:
snip...
Tungsten disulfide will not have worked. The number of cycles and the stress the surfaces are under mean it took a coating with durability and slipperiness that far exceed Tungsten disulfide.

DLC is needed because it offered unimaginable properties relative to the old coatings.

Yes, very old IP, as that design was back in the 70's and that
was the latest and greatest.

It is soft and can be nicked.

Am not up on, more did I know of DLC's till you mentioned it.

I know for sure it is on the cam and contact surface, suspect it is on the piston and sidewalls, but have no independent confirmation.

That is my assumption too, more in light of the cost comment

But that brings me back to ask why it is needed. There are other ways
to solve this, as this is NOT going into a missile or fighter plane

A critical issue is surface prep --- as whatever defects tend to be faithfully replicated.

In the old days, before you coated, a part is blue printed.

AFAIK, that is not good enough for the tolerances in the CP4 series, where tolerances require surfaces to be extremely tight in terms of spec and smoothness, etc.


What I do not know:


Is the part even machined to "round" or "flat" or is there a bag of tricks involved at the level of microns?

Yes, know this well.

One of my machine shops, which specialized in micro stuff (aptly named
"Micro Machine") received an emergency call form a supplier to a NASA
contract that I too was supplying...the portion that they needed to
be fixed had such a finish and tolerance (roundness and straightness
that just chucking it would have destroyed that tolerance).

Hypothetically, the piston cylinder could have a face that is machined ever so slightly from flat at the cam end, so it turns ever so slightly to equalize wear on the round bore.

Or, the cam lobe can be ever so slightly inclined, to force the shaft back toward a pressure seal.

That is the actual design of most all push rod cam/tappet setups. The
tappet is set off dead center and the cam rotates it to even out
the wear patterns on the bottom of the tappet. But am assuming on my
7.4L big block with roller tappets, it is dead centered to allow the
rollers to stay square to the rotation of the cam

Many of these things are possible, but without knowing the engineering data, we can only speculate --- very hard to see this kind of tweaks from sample reverse engineering.

That is all we can do as out siders...to speculate and make assumptions
based on our background and education (street based too)

Forensics or reverse engineering is not taught much and a tough thing
to teach/learn.

Why so many questions and re-stepping in the original engineering step
(now speaking to those who have commented on not understanding what
the heck we are talking about)

I have now learned that this era (don't know how long) has H2O membrane
barriers (filters). Also now wonder why there is a H2O problem, which
then says these membranes are either not working or circumvented in
some manner...which then leads to the question of why did they keep
the H2O separators down stream from these membrane filters and then
that leads to ask why did they deny Rick's claim based on H2O in his
system????

That then tells me that the OEM(s) knew long before Rick took delivery
of his truck. As it was part of the OEM equipment. Which then says
they have NOT solved nor either found or understand the root cause(s)

It all, from this dialogue points to H2O and some how creating a failure
of some area in the pump that destroys the coating (questionable) to
then destroy the base metal (absolute, as the OEM has stated that).

Using the OEM's positioning, H2O based failure, it all then points to
the pump.

Then inside the pump ask where and then why.

Then the DLC. An exotic coating that is very, very expensive to say
it is selectively placed at 'THEIR' suspected source or point of failure

That is something we do not know for sure and can only guess. I think
it is in the cam/roller and a close second in the piston/cylinder area

Currently this discussion is spidering out from that center of failure
trying to find possible sources directly or as ancillary contributors
to that failure(s)

Am positive that the OEM has ID'd it down to H2O both from their positioning
in their denial of Rick's issue to the last few pages where I found
that the OEM's have H2O barrier/filter membranes in the particle filters

One OEM even has two filters in series, which cements the H2O point,
as that is double the cost for filtration on this single fuel line

In narrowing this down, ask why the previous pump did not have this
issue, that we know of.

Cavitation is my #1 and am getting more and more confident that it is
with the comments of 'timing' of the pump to the injectors...which to
me is purely missing the boat, as how do you time 8 pulses that are
random to the pump, which has one, maybe two pistons. Do the matrix
of how you can time those two pulses and the complexity of the controller
and sensors to time them.

Both the mechanical and electronics needed to do that (I'm not sure it
is even possible no matter how much money you throw at this).

Find that there was a gear pump and was my first solution to this whole
mess.

Another point is that there are well known solutions to the cam/roller
contact PSI problem. That is to reduce the PSI. That then says to both
increase the dia of the contacting components and/or increase the width,
thereby increasing the surface area, thereby reducing the PSI

Am satiated enough to say it is in the pump and at either/or both the
cam/follower and piston/cylinder.

Am thinking truly penny wise, pound foolishness in trying to keep the
same pump, and/or form factor that they have overly band aided the heck
out of it. To the point that they have dug a hole so deep that they
are now working at adding width to that hole.

That is in light of the cam shaft bearing and it's seal. If there is
such a severe condition in there that they have to go to the measures
they have to excise H2O and the exotic (expensive) plating that they
may have missed yet another source of H2O...that cam shaft bearing seal(s). Plural, as there should be a min of two for any shaft of that
architecture

Repeat that I'm not a diesel guy, but am a long time designer and know
that all designers LOVE far out stuff. The more exotic it is, the more
fun there for the designers...but...too often designers and teams get
lost in these rat holes

Key is to have someone with the ability to bring them back up to the
big picture and is where I think they have failed to do and continue
to band-aid over band-aid over band-aid with their CUSTOMER (therefore
reputation) taking it on the chin or shorts.