What is the purpose of the screen in the HPOP?

Good to know. Since the HPOP only holds ~1.5 quarts of oil, would it only take a couple of minutes to cycle the amount of oil in the pump, out and replace with fresh oil?

 

To catch any pieces of any internal engine component that may break off and keep it from going into the HPOP and injector passages. Kinda like the screen at the fuel tank pickup tube that keeps larger debris from passing through the fuel pump.

Pretty much, yes. Anyone who has blown an HPOP line while driving down the highway can tell you how amazingly fast your engine oil disappears. I had that happen once, and within a matter of minutes, 10 quarts of oil was dumped out, leaving me stranded on the side of the road.

 

And, two pumps spinning at idle, takes less than a minute

 

IIRC, I read that a guy on this board removed that screen. Seems like a good thing to have.

 

Older ones didn't have one, so I guess it's not really a big deal to keep or remove it. I guess that if something fails, it could possibly keep shrapnel from going further into the injector system. But then again, if you have pieces like that floating around in the oil, you've got some big problems anyway.

 

You guys knew I would be along eventually. All I will say now is that this topic still amuses me to this day.

Let's see, from what I have read: I sucked 1/2 qt out. Reservoir holds 1.5qts. All looked good. There is a screen in there. Can't suck it all out. My HPOP oil looked just as good as the pan stuff. Sediment settles where?

At any rate, I have not done the investigating I needed to do on this so I will STFU. Without pictures this post of mine is worthless.

I am changing oil from Rotella syn to Schaeffers syn very soon, weather is simply too cold right now. I will be sucking every bit of old HPOP oil out. You folks do as you please.

To quote someone who knows who he is, I see the difference in doing this as the difference between being a wrench turner and a true enthusiast. This quote comes from a thread on the power steering fluid flush and choice of fluids. He knows who he is.

 

The point to think about here is the volume of each pump. The LPOP must exceed the HPOP pumping ability in whatever unit of measurement (vloume) you decide to apply except PSI. How else can one explain it's ability to keep up with the HPOP even with big oil?

It does. It also has a fair sized reservoir that lubricates the gears, (no timing chain here) that drive the HPOP. This is a cam gear, driven by the crank. Think this one over. Now think about where the reservoir gets it's flow from the LPOP.

Again, I need to document my thoughts with pictures to illustrate my point. A well maintained engine will exhibit little signs of sludge due to regular changes, but there is a no man's land in there if my thoughts are correct. The average HPOP sucking never even gets close to the lower area of the reservoir.

EDIT: the HPOP willl never turn over all the oil there either due to where it's intake is at the top of the reservoir. This really seems pretty elementary to me, but I may be missing something.

 

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There must be a suction and return on the HPOP. Where are they located on the pump? The suction or supply comes from the LPOP and is located at the top? I find it extremely difficult to believe that a pump with a particulate screen separating the bottom end from the top end wouldn't circulate and flow all fluid through it.

 

Well you better get your believer meter fixed until you can post otherwise with pics from what I am saying. The HPOP reservoir is the entire front cover until I see different. That is how the crank, cam, and HPOP gears get their lubrication. Show me I am wrong. The input for the HPOP is way on high. If I am right, the reservoir extends way down low.

 

Oil enters the top of the resevoir through stand pipes in the illustrations ,,I don't know what year these apply to

 

You make a good point here Mike. Anyone know the flow rate of the LPOP? I'm guessing it's a pretty high rate (low pressure through a larger opening = less psi).

 

This is how I interpret the first LP diagram:

The LPOP supplies the bottom end of the front of the motor around the crank which acts as a centrifugal pump and shoots it throughout the long block, then it goes up to the cam and back into the top part of the reservoir via an internal supply tube which directs the oil to the top and over keeping the oil circulated to be prepared for the HPOP.

Then in the second HP diagram:

The HPOP appears to be mounted on the back side of the reservoir, pulls the oil out of the reservoir (which appears to be the top portion of the front of the motor), pressurizes it and sends it to the high pressure oil lines along the top end of the motor.

I don't see how any oil remains stagnant in those diagrams.

 

Good stuff....

 

Actually Mike, no, it's not that big of a reservoir. The bottom of the reservoir is rather shallow and stops just above the HPOP gear (above the front cover). Move over a bit to the driver's side of the gear and there is a dip in the reservoir, where the screen sits, and it's also where the oil flows to the HPOP itself. But the HPOP gear, crank, and cam gear are 100% separate from the HPOP reservoir, and do not get lubrication from any oil in the reservoir.

Look very closely at the picture that Action posted. The number 1 points to the reservoir, and look just under that arrow, notice the line drawn that goes through the reservoir? That is the bottom of the reservoir. No oil below that line.

Oil comes in through the top of the reservoir, and flows out the bottom. That's the best circulation method to keep out sediments, sludge, etc. That's why there's no need to change out the HPOP oil, there isn't any sludge buildup. Unfortunately , watching those Powerstrokehelp.com videos, the guy tries to make the viewer believe that there is a ton of sludge in there.

When I yanked out my old HPOP and put in the Terminator setup, I had to remove the reservoir in order to unbolt the HPOP gear. I got a very good look at the internals of the HPOP reservoir, oil feeds, etc. With about 100K miles on my truck (at that time of swapping HPOPs), there was no oil sludge inside the reservoir, or anywhere else.

It's my firm belief that those videos are mistaken. Every one of those videos has many many errors contained in them, and can severely misguide a PSD owner. If a 7.3L has sludge built up inside the HPOP reservoir, it's from lack of maintenance, and there will be massive amounts of oil sludge elsewhere in the engine more vital to longevity. Proper oil changes and maintenance will keep the engine and HPOP system clean. Many 7.3L's have already marched well beyond the 500K mile mark way before the concept of HPOP oil changes was ever concieved.

Anyway, that's my 2 cents. If someone wants to change the HPOP oil, then it certainly doesn't hurt anything. But it doesn't help anything either, and takes additional time and effort to do something that won't make any difference to engine/HPOP/injector life.