Pete, this turned into a good discussion about oil movement in the HPX. I think another way to see if oil is flowing through the HPX would be to install a gauge in each head where the HPX connects. Then start the truck and see what the difference is for each head. I don't know if that is possible without something like the AE hooked to the gauges/sensors. I also don't know if each injector is using the same amount of oil to fire it. I think this is trying to split ATOMS.

Hopefully you smart guys can come to some kind of agreement/conclusion on this.

I'm sure there is some kind of flow meter that is small enough to work on this.

 

I've read up to this point.
Another thing to remember is that if you apply enough pressure to a fluid with air bubbles in it, the air will get absorbed into the solution.

 

I don't know if you have a hard line, but the peak of the M is about 1/3 of the line from the end, the in addition there is the fitting, so it's still going to take a fair volume of oil to push it on out. assuming it will "migrate" on it's own to the top of the M, Isn't it's "migration instinct" going to keep it there unless there is a considerable oil flow?

 

That's good thinking, Rick, and I've thought about that for a while as well. However, I don't think we could really measure that pressure difference due to the exceptionally high frequency of the injector firing sequences. Even with AE, I'm not so sure we can really see the true time between the pressure peaks and valleys because of the difference in AE's data scan rate, the PCM's scan/report rate, and the frequency of injector firing sequences.

Also, as much as I would love to be able to do that, I don't believe that info by itself would really give us what we're looking for. We would have to take the pressure differences and then start making assumptions about friction losses in the hose in order to do a pressure versus flow calculation, but we need the flow values to determine the friction losses first - it ends up in a tail-spin of circular math that is difficult to resolve.

All I need to do is find out how much oil gets used for each injector firing event and I can go from there to mathematically mimic those head-to-head flow pulses.

 

My line is a hose, and IIRC, the peaks of the "M" are right at the bend on the fitting, so my peaks are much closer to the end of the travel path. Good point, though, clux.

And, yes, for if the peak is much farther from the end than as with mine, it would take more volume to push the bubble past that point. Again, even though I don;t know the real volume of the flow we're discussing, I think we all believe that the pulsation packs a pretty good punch which would provide a pretty high motive force to shove the bubble even downwards in a line.

Dan, you bring up a valid issue, too. Technically speaking, though, at the elevated oil temperatures in our engines, any "dissolved air" gets converted to "entrained air" in the form of larger bubbles (larger only in comparison to the microscopic "dissolved" air bubbles) due to the engine's higher operating temperature causing the air bubbles to expand. This "entrained air" then becomes a potential source for frothing or foaming when the pressure is reduced before the oil is cooled again. Really, though, this scenario of converting dissolved air into entrained air doesn;t quite match the HPX line issue we've been discussing, but it does reveal another complicating factor in the oil system's performance.

Here is a good link on the issue of air in oil. Effects of Aeration on Industrial Lubrication Equipment

 

Not that it makes a big difference to this discussion, but we need a do-over on the math here.

I didn't get out the slide rule myself, but the once-over "reasonableness" in the calcs doesn't work for my ol' gray matter.

Edit: I got out the calculator:

Area = pi x radius x radius

Assuming the I.D. (inside diameter) of a 3/8" tubing is actually 3/8" (or .375"), the the radius (half the diameter) is .1875".

The radius squared is then .03516

Multiplied by pi (3.14159) leaves .11045 sq. inches.

Thus the volume for one inch of this tubing is .11045 cubic inches

And the volume of ten inches of this tubing is 1.1045 cubic inches.

Plugging that into Pete's Gene-ism, that bubble is a LOT smaller than we thought.

Pop

 

Dang it, in my attempt to run through it, Marv, I calculated the circumference instead of the area on that issue.... Great catch!!!

 

I would agree that at higher pressure the bubbles would get smaller ,very small in really high pressure.And flow through lines more freely. But Absorbed? What pressure would absortion(desolved) be? Been a long while since school.
Or is that what you meant.

When i made up my HPX. i was thinking about putting a T in the center of it. So i can put a bleeder on it. My thinking was the air will just be stuck in there from equal pressure on both sides. (why some folks say at least 200 miles to get air out) Yes there is hydraulic valves working very fast and creating shock. But there are equal amount of valves(injectors) on both sides(balanced). And with the equal length hoses, Same restrictions feeding each side. What would the offset be that would cause the oil to travel through the HPX? I think the pump could be the factor, does it pump the excact same oil out each port. (internal orfice restrictions) or a slight differrence in injector volume from one side to the other..

 

Dan (danskool)... different fluids will actually absorb air under the right conditions, much like brake fluid will absorb moisture from the air over time. From what I've read about the oil, though, the dissolving of air into oil happens more easily at low temperature conditions when air is denser. It's harder for the absorption process to take place at higher temperatures. If you have air absorbed into an oil supply, the action of heating up the oil will cause those microscopically tiny air bubbles to grow and you'll end up with potential frothing or foaminess because what had been "absorbed air" becomes "entrained air".

The biggest difference from what I can tell is just the size of the air bubbles between these two conditions, the absorbed condition having air trapped on a molecular level which means it doesn't have enough bouyancy to overcome the chemical attraction to the oil molecules and float to the top.

 

AH.. learn something every day, Thanks for clarifying. . So when absorption happens it shows up as Froth? An oil milkshake. I thought it happened with air and erratic movement. Not pressure or lack of. You can take air and oil, put it under pressure and get Froth? But if you take air and oil and Shake it in a bottle you will for sure get froth/foam. Ok now i am confused.

 

Dan, read through the link I posted up in post #65... that might help clarify things a bit, too. It's not as simple as air being in contact with oil... the HPOP gear mixing/shear forces, etc. all come into play.

 

Well I'm not sure what an HPX or a HPX mod is but it sounds to me like you guys are referring to the high pressure pump and the lines going to the injectors (Please correct me if I'm wrong and educate me as I'm new to this fantastic 7.3 motor) and I think I'm missing something else but I found this video and it talks of changing the oil in the high pressure pump reservoir to help get the sludge and junk out of that area and so you have a 99.98% oil change and longer lasting injectors.
POWERSTROKEHELP.COM - The Information Source for Ford Power Stroke Diesel Owners

 

OH NO.. not this again

 

Welcome to FTE!!

We have come to the conclusion that there is some good information there but some of it is incomplete and may be a "bit" on the misleading side. The oil in the HPOP gets cycled through on its own. When you change your oil yes there is some of the older oil still remaining in the HPOP but the amount is so small that it dosen't make a difference. Unless there was something seriously wrong like ,IMO, coolant in the oil.

The HPX line that we are discussing here is a line that goes between the high pressure oil rail in an attempt to equalize the pressure between them.

 

Dan, think about what's happening sequentially. Slow the process down into steps, like this:

1. Injector in passenger-side rail fires, lowering the pressure in that oil rail. Stop here. Remember, only one injector fires at a time.
2. WITHOUT the HPX, only oil coming from the HPOP is available to bring the pressure back up. WITH the HPX, oil from the other head is also available bring the pressure up.
3. Injector in driver-side rail fires, lowering the pressure in that side. Now oil from the passenger-side head is also used to bring the pressure back up.

We know that 6 & 8 fire sequentially. Both are on the same side of the engine causing the fuel problem, so that means two injectors fire on one side one right after another. I would assume that means two on the other side also fire right after another.

I guess I could look it up, but does anyone have the firing order handy?