It's all just speculation ........

It's not a high failure rate, just catastrophic when it does occur.

If I remember correctly Eaton was the original supplier to Nav for the lifter, and I believe they shut down manufacturing and the supplier became Delphi. Aftermarket has a few.

When I was looking around I didn't see other applications of this particular lifter having lifter failures. So are we the highest stressed, by speculation. It's going to take 100 years for enthusiasts to trial and error a solution considering the low failure rate.

 

What would be nice to know is if anyone that has the shorter push rods
has had any issues.

 

That could be telling for sure, especially if they replaced lifters when they installed the push rods.

 

WHen this first happen to Anthony I was thinking that do to it
being the back lifter that crapped out on all the cases that were
taked about that maybe it was a lack of oil. Sort of like some of the (small block?)
race engines that they solved with adding a second oil line into the
lifter oil gallery at the rear of the block. But in out case there is not
an open valley to plumb oil lines in. One would have to find a way to
access the rear gallery plugs and still have the clearance for the cam
gear. The gallery plugs seem to be right behind the cam gear and there
is not a lot of space for any fittings back there. But I am not sore on
that because I don't have an engine to play with at this point.

You know even if they did not change the lifters when going to the
shorter push rod not having a failure would say something too.
Now if we hear on a failure with the short push rods the one question
to ask would be "Where the lifters replaces also?"

 

There's been a lot of speculation. I don't get where the pushrod should make a difference. It won't change anything within the rocker box. It does however slightly soften the impact of the point where the valve starts to open as best I can theorize.

However, if the dimension between the cam lobe base circle and the rocker are the same between the 6.0 and 6.4, a shorted pushrod ain't helping the 6.4L.









The second guy in this thread shot confirms what I had thought I read, although maybe it was this thread I read years ago.

 

general rule of thumb i was taught was 10 psi per 1k rpm. we always made a modification to the spring if we couldn't get a high pressure/volume pump.

i have seen roller lifter fail for only a few reasons in my 25 yrs wrenching, over reving, to high of spring pressure, debris from other part of engine,poor oil change history and poor oil choice.

 

As you may recall Anthony had one disintegrate on him.

 

I would agree in most motors the oil pressure we see is acceptable, I'm just speculating in these high load situations of the 6.0 and 6.4 lifters, unseen with even the brother 7.3, there should have been more study. Diesels have an exclusive market to the emergency service industry, and yet in those long idle conditions it's reported to have a logarithmic failure rate compared to normal driving traits of consumer and commercial owners.

Often it's mentioned that motors pulled from ambulances are good deals due to their scheduled maintenance and low miles. Maybe not so due to idling and hours.

Valvetrain forces are not altered by any change in programming, an ambulances low HP is no different then bigger shot injectors and programming. So if the issue is consistency in materials and machining the failure rate should be the same, and maybe there is a base failure rate attributed to that, and we see that with consumer vehicles. But a long idle high failure rate I can only see being a lubrication issue.

So if the roller lubrication is by splash, which with its tray means oil flung off the crankshaft in a 6.0, the paradox is will thinner oil with its lower pressure or a higher viscosity oil with its corresponding higher pressure (+5psi) provide a more lubrication of the lifter roller.

Damn if I know.

 

My theory is the 6.0 shears oil so bad that with high oci's, over 7500 mi, these engines are being started dry of oil. Anything splash lubed will be the first to suffer. Thin oil will run off and and leave the surface dry in a short amount of time. If they sit long enough dry corrosion sets in and only compounds the problem. When I see my idle oil pressure drop, I change the oil, regardless of miles. I have never gone over 5000 mi oci and T-6 was junk at 3500 mi.

 

Back to Anthony again. As I recall he used blended oil and changed it
at very regular intervals. So much so that if the milage came up they
would pull it over and do an oil change on the spot. Why oil brand they
used I don't know. But as for letting the truck sit. There no way they did that.

 

Anthony might not really be the best test case, he had the heads off his '06 right around 100k IIRC the first time after buying it with 85k, then the major rebuilds later on. If he cut the heads on the first job then lost a lifter, that would seem to be a point towards using the shorter tubes.

I remember him saying he was running 15W-40 on 7500 mile OCIs, at least for awhile. And again, he's had all the bearings done at least once so his engine at 440k and 800k after the major jobs with low hours for the new miles could really be tighter than someone running around with 300k and a ton of hours on their original bottom end.

He also has a manual in his truck, and not saying HE abused it but in the first 85k someone could easily have over-revved the engine or just red-lined it enough that ultimately dropping an exhaust lifter could be a factor of more than just the oiling of the roller bearings.

 

Would there be any potential benefit of raising the idle rpm in regards to lifter health?

 

Slick 50 will fix er ! /sarc

 

Since all we have is speculation, I’m not sure that would help. In the end it may come down to variability in manufacture, or something else we as owners can’t control.

Another SAG would be the rollers are pushed with less margin to proof load, then some normal manufacturing tolerance on the lower end gets can get into trouble.

 

Now my ultra low miles (sitting a lot so many dry starts), blending my own oil, reading this and other threads on lifters failing in 6.0s has given me another thing to worry about: I'm hearing a definite chirp on every shut down...

A new Superduty with a 6.2 gasser is starting to sound like life would have less worrying and would fit our usage style versus ANY diesel...

I would miss the sound and the power, I really love my truck... Maybe too much FTE reading = extreme paranoia

Ugh...

It probably would be cheaper to keep the truck, go to the strongest film strength oil allowable (more important imo than oil pressure alone), and when it blows up, fix it and move to a gasser then...

Sadly, Scott