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I think I have an equation figured out that will let us determine the theoretical displacement of the pump with a few simple measurements. Before I let this fly, I'd like someone to measure the center to center distance of the two gears in some semi-accurate manner. Thinking of a digital calipers, having the two gears installed in the housing, measuring from the outside of one shaft to the outside of the other, then subtracting one of the shaft diameters. This should give the center to center distance assuming the shafts are the same size. If this measurement is 2.864 inches then the equation should be good with just the tooth count and the thickness of the gears, if not, we'll have to go through the above process.

If the same kind soul could also measure the width/thickness of the gears, I'd also appreciate it.

Sounds like someone figured out that the reduction of oil pressure on the later engines is due to higher flow allowed to the turbo charger. We can start breaking down how much flow is going where if we know how much flow we've got available in the first place from the pump.

Thanks!
 

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RickDLance;1760219; said:
The gear width is .510. I'll try to get you a c-c tomorrow.:)

Any luck with the CC'ing?

If you are able to determine the radius on the teeth and the diameter of the gear, I can draw this in MasterCam, then analyze the volume. I can then add thickness to the gears, reanalyze, and determine what the additional volume is.

Are these parts Metric or English? .510" comes very close to 13mm.
 

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Im not 100% sure, but 99% sure that All dimensions on this engine are metric.
 

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Has anyone tried using a larger sump oil pan? More oil (say 15 qts. +), would take longer to heat up, lose viscosity, and cause the lower oil pressures after a hard pull. Just thinking aloud here.

What's the status anyway? there's been no activity on this thread for a while now.
 

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i got flamed on here for wanting more oil pressure.now look.everybody wants more oil pressure.
 

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flames

sideswiper;1815307; said:
i got flamed on here for wanting more oil pressure.now look.everybody wants more oil pressure.
Some people on here are into a little premature flaming!!!:D:D:D
 

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sideswiper;1815307; said:
i got flamed on here for wanting more oil pressure.now look.everybody wants more oil pressure.
King Pin;1815381; said:
Some people on here are into a little premature flaming!!!:D:D:D

It's not higher pressure they seek, it is higher volume to maintain the stock pressure. :)
 

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Discussion Starter #69
Diesel_Day_Dreamin';1822616; said:
It's not higher pressure they seek, it is higher volume to maintain the stock pressure. :)
Ding, ding, ding.;)

Sorry it took so long, but here are the rough measurements.

Outside gear dia is 2.044, and the valley dia is 1.241. The rad at the bottom of the valley is aprox. 5/64. Hope this helps.:)
 

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The picture RickDLance posted shows a truck with oil pressure <30psi by the factory gauge after a long uphill pull with a heavy load. Since the pump is mechanical, the pressure should maintain as long as there is good supply. The pressure relief valve and squirter valves are all designed to ensure good pressure to the rotating assembly (presumed at least 29psi from the squirter pressure valve setting). The oil will be plenty hot at the end of a long uphill pull and that will lower oil pressure, but is it reasonable that the oil pressure will drop below 29psi due to hot oil alone? If not, then the problem may also arise due to poor draining back to the pan.

Not sure if this is right, but I thought it may be worth discussing.
 

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I know this is an old thread, but did anything come out of this?

A few things I've learned (though on a 2012 LML/LGH) directly from the service manual.

1) Oil Pressure Minimum - Hot - at idle = 7 PSI
2) Oil Pressure Minimum - Hot - 1800 RPM = 28 PSI
3) Oil Relief Valve Opening Pressure = 64 PSI
4) Piston Cooling Jet Valve Opening Pressure = 26=31 PSI

Now, on one hand I can see that you don't really need piston cooling when at idle, but on the other hand, it sure would be nice for there to be enough oil pressure/flow to open the cooling jets below 1800 RPM...
 
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