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90T
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The oil pump relief valve shimming was debated to death 10 years ago for improving idle pressure and has become religious. There is no valid engineering behind it.
 

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90T
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are u saying that braided 8an on DM is garbadge? i just got one was planing on using it...:(
Yes, its absolutely dangerous. Just like pushlok hose that loses its pressure ratings at high temperatures and should never be used in oil systems, immersing braided rubber hose in hot oil is idiotic.

Here is some interesting reading on the 7M oil system

 

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Yes, its absolutely dangerous.
Just an FYI, the new DM hose that you have crossed out on the previous page is a crimped PTFE hose that's acceptable for submersion. So long as it's not hitting the crank counterweights it'll last.

Since the pump is constant volume the banjo fitting is IMHO right up there with shimming the relief valve in terms of uselessness.
Explain. In detail, if you will.
 

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Discussion Starter · #144 ·
Good news on the O ring. Toyota still offers them and I've got one on the way for tomorrow morning. Kinda pricey for a single O ring at $3 but worth it for peace of mind at this critical juncture. It needs to handle perhaps 100psi of vacuum when cold as air tries to sneak past it into your oil flow.
 

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Discussion Starter · #146 ·
Wouldn't 100psi of vacuum on one side of the O ring create the equivalent pressure drop across the O ring that 100psi of pressure does (less atmospheric pressure, of course) in terms of force displacing the O ring?
 

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You can create a pressure differential of 100psi, but you wont be pulling more than -14.7psi (or referred to as 0PSIA). Additionally, gear pumps like this are generally not capable of pulling anywhere near that kind of vacuum. General rule of thumb is -7.5psi.

Going off basic o-ring seal designs, the generic SAE o-ring would be good for 1000+psi, or substantially more than the oil pump is capable of pulling in vacuum. The main failures are going to be temperature related or improper size related.
 

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90T
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Explain. In detail, if you will.
1) The oil relief valve in the pump is spec'd at 67+/- 4 psi. It will be shut tight at low engine speeds. Therefore it cannot have any impact on idle pressure, yet people religiously claim their idle pressures zoomed up when they shim it. Unless the valve had actually failed in every one of these cases (unlikely) then it is impossible for it to have been the cause.

The real pressure limiter on the 7M GTE is the 40psi oil cooler bypass. That will limit your max pressure to 40 psi and replacing that with a conventional oil-water cooler setup or a thermostatically regulated full flow oil cooler makes good sense.

2) No production engine I am aware of has a flexible hose internal to the crankcase to carry hot oil. Why? Because it cannot be inspected for degradation or leaks, it has a known limited lifespan, and it needs to be significantly derated for high ambient temperatures and the presence of VOCs. Teflon is no cure for any of this. Those hoses derate at 150C which is plenty attainable inside the crankcase. If you really want to do this then use an AS1424 all metal hose or buy the AZP all-metal solution for $60 more.

3) If the 40 psi oil cooler circuit is deleted, obtaining ~70 psi (i.e max pump pressure) has been readily demonstrated. This proves that the pressure drop across the banjo-bolt fitting is negligible even at full flow (oil flow proportional to rpm since its a constant displacement pump). The area of the 4 holes in the banjo bolts exceeds the diameter of the stock pipe to the block so it never was likely to be a problem anyway.

The Toyota 2GR-FE V6 used 3 hoses for the oil cooler and the VVTI actuator. Google it to see how many engine failures were caused by undetected pinhole leaks and the resulting recalls to replace these hoses with metal pipe versions which were standard in the Lexus cars using the same engine.
There is also a posting on this site or SM that I cannot find where someone with the ss-braided hose setup lost their engine when the hose ruptured.
 

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Hardcore Night Warrior
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^ So, what would you suggest to use then? Brand new stock components?
 

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1) The oil relief valve in the pump is spec'd at 67+/- 4 psi. It will be shut tight at low engine speeds. Therefore it cannot have any impact on idle pressure, yet people religiously claim their idle pressures zoomed up when they shim it. Unless the valve had actually failed in every one of these cases (unlikely) then it is impossible for it to have been the cause.
Agreed. Only way to increase idle pressure is to increase pump volume or speed. Or flow restrictions downstream, or thicker oil.

The real pressure limiter on the 7M GTE is the 40psi oil cooler bypass.
This thing is terrible.....

2) No production engine I am aware of has a flexible hose internal to the crankcase to carry hot oil. Why? Because it cannot be inspected for degradation or leaks, it has a known limited lifespan, and it needs to be significantly derated for high ambient temperatures and the presence of VOCs. Teflon is no cure for any of this. Those hoses derate at 150C which is plenty attainable inside the crankcase.
Where precisely do you get this information of where PTFE hose must be significantly derated at 150°C? Parker rates the most basic PTFE hose with a single SS braid at 290psi at 445°F (230°C), and this hose is built to the same SAE 100R14 specs that the vast majority of automotive braided PTFE hoses are made to. And unless you can provide a specific study about VOCs degrading PTFE that claim is laughable at best. There's a massive amount of industry using PTFE because of it's resistance to things like VOCs.

This proves that the pressure drop across the banjo-bolt fitting is negligible even at full flow (oil flow proportional to rpm since its a constant displacement pump). The area of the 4 holes in the banjo bolts exceeds the diameter of the stock pipe to the block so it never was likely to be a problem anyway.
While the 4 holes do have approximately twice the open area as the pipe, the fact that at best one of those holes is lined up with the direction of oil flow significantly reduces the actual flow. Pressure drop and turbulence are a thing.

Your free to take the info below and do the math yourself, but I'll abstain from derailing this thread further.
259671

Type SWVE is the most comparable to the OEM banjo bolt

Sharp elbows like the one used in the ARZ kit:
259681


And tube bends (-8AN fitting is usually 2)
259682
 

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Discussion Starter · #151 ·
I'm appreciating the technical aspects of the aperature part and I'll make an interesting offer. Captain - take this same info and start a specific thread with the info on the elbows and such and let's see if we can contribute to the forum knowledge on this banjo fitting thing. I'll figure out a way to spin a bunch of oil through my 7M pump using a drill and rev counter and a timer or a measurement which we can discuss on the thread. I've got the Drift Motion hose, I've got the pump on the bench, and because it's time for a couple oil changes, I'll have a couple gallons of used motor oil. If you guys and others can agree in a test regimen, I'll do an actual pump comparison though we'll see if I can generate meaningful speed of the pump. What do you think? Already I am wondering how to spin it without potentially damaging my drive gear though.....
 

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90T
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Where precisely do you get this information of where PTFE hose must be significantly derated at 150°C? Parker rates the most basic PTFE hose with a single SS braid at 290psi at 445°F (230°C), and this hose is built to the same SAE 100R14 specs that the vast majority of automotive braided PTFE hoses are made to. And unless you can provide a specific study about VOCs degrading PTFE that claim is laughable at best. There's a massive amount of industry using PTFE because of it's resistance to things like VOCs.
I agree PTFE is pretty amazing and resistant to acids bases, and high temperatures. However, there are papers out reporting of interaction of charged PTFE surfaces with metal ions which cause degradation of PTFE. This occurs in water solutions, and there is plenty of condensation in the witches brew of the blowby stream. We've had problems in etchers here at my work with PTFE tubing failing mysteriously and the root cause was aqueous gas streams with metal ions present. You are free to use whatever you want in your engine, but that is not ever going in mine.

Here is a derating curve from Aflex Corrflon tubing.
259683
 

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90T
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I'm appreciating the technical aspects of the aperature part and I'll make an interesting offer. .....
This would be great. The first thing to do is a back of the envelope feasibility analysis. Oil pump actually can consume a lot of power. We can use this calculator to estimate it.

If we know pressure (say 70psi) and efficiency (90% is reasonable) then if we know gph of the pump we can calculate how much horsepower you will need to turn the pump. It may well be bigger than you think, but let's try to calculate it. Anyone know the gph of the 7Mm pump?
 

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90T
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While the 4 holes do have approximately twice the open area as the pipe, the fact that at best one of those holes is lined up with the direction of oil flow significantly reduces the actual flow. Pressure drop and turbulence are a thing.
Yes they are. And the tortuous path of the oil galleys and the pump discharge itself are none too different from the banjo bolt. I have FEM analysis tools here that can work better than the models if we have 3D models of the fittings, but really I think the measured oil pressure (70psi) of engines without the cooling bypass already tell us its all fine and the pressure drops are not an issue.
 

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Discussion Starter · #155 ·
Hey, one of you guys start a separate thread on that fitting and let's get a plan together. Yes it may take more power or speed (pick one) than I can generate with my drills, though I do have a 75th anniversary Milwaukee that is a true beast that is known for spraining wrists. So, new thread. Tx.
 

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Discussion Starter · #157 ·
My thrust plate is super tight. At the tight end of the acceptable range. The manual says check the clearance between the plate and whatever they call that other round part. My shaft's bushings were also on the large end of the range, meaning they have not sustained much wear. The car was well taken care of by and adult owner before it was parked and this was a good sign. Anything else I should know about that plate?
 

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90T
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There is an upgraded roller bearing plate, but if you have no wear then you should be good. Sometimes those plates show excessive wear.
 

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@Captain suggested this after asking him a few questions

"f you haven't replaced the thrust washer on the OEM pump driveshaft I highly recommend replacing it, and the best option out there is the one made by Technico Racing. If the OEM one fails, 9 times out of 10 it's taking your motor with it."

looks like a quality part and a very good find. I think their dealing in aus currency so turns out to be like 100 bucks usd.

thank you Captain
 

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Discussion Starter · #160 ·
So the oil pump driveshaft drive gear gets pulled against the block by the gear drive on the pump end, and that measured gap on mine was ideal for an oil gap/film. In addition, oil literally runs down the face of the block there like a waterfall then into the pan below to lube things in that area. At 124k, that lack of wear shows pretty good design of the part and its oiling for its needed function, so I'm confident all is well and will remain so.

The linked product is interesting and valid if failures are showing up on high performance engines, though this component's increased wear/heat issues would simply be a function of higher RPM/higher oil pressure. Unlike say exhaust valves and pistons on a pumped up engine which take HUGE abuse with higher output, this part just merrily spins away, only feeling increased pressure from high RPMs which it is clearly designed to handle. So it's kinda out of the upgrade path in my opinion when you hot up an engine.

Kinda like water pump bearings which simply experience higher RPM and a bit more heat on a high output engine, but not a part that seems worthy of a "performance version" bearing to support a spinning shaft.

I'll be surprised if someone reports increased numbers of failures at the bearing as it seems well designed as increased oil flow rates accompany that higher RPM/higher oil pressure, which provide commensurately higher levels of protection to this part. Dunno.

Also, if these shaft failures are the actual bearing wiping out - it would be good to know and get those roller bearings in the link. But if they're snapping shafts or stripping the brass drive gears that's not going to be cured by less friction at the front shaft bearing.

One pro tip not in the manual was I lubricated my thrust surfaces on the shaft before installing it so it's not spinning dry on startup. Surprised the manual doesn't say anything but I suppose anyone this deep into a block should have the skills to see a cleaned part with dry friction surfaces and say "Hmm, a few drops of oil here make sense".
 
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