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Old 05-05-2010, 04:37 PM   #1
masterx81
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Default Oil restriction in bearing galleys

Hi!
I've already asked this in a thread, but i want to investigate a bit more on this.
On the holes that connect main bearings to the main galleys, there is a restriction at the bottom of the hole:
For example, the hole is 7mm, but it's not drilled through the whole depth, at the bottom there is a hole with smaller diameter.
This can be flow control holes, that try to balance the flow/pressure at the bearings. This theory can be validated by the fact that only n°5 hole isn't restricted (as is the far from the oil pump).

I haven't seen this type of restriction in any previous engine that i've found (only european 4inline engines).
I think that the main restriction in the system will be the bearings itself, and that any other restriction, can decrease flow. With a well built oil system, with good pressure (measured at the farest point on the oiling system), can this things actually hurting? Especially on built motors with increased rod/main clearances, or in system where the oil viscosity is different, on in increased pressure systems?
Can hurt removing them?

Thanks!
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Last edited by masterx81; 10-30-2017 at 09:37 AM.
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Old 05-05-2010, 06:02 PM   #2
Gixxer1K
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It would seem that pressure is more of a priority than flow on the bearings then! Pretty logical huh?
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Old 05-05-2010, 08:45 PM   #3
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Uhm, but the restriction will also limit pressure...
If the bearing is more restricted that the orefice, the pressure drop will be minimal, and also the flow restriction. If we increase flow at the bearings, we are also trying to put more flow over the restriction, and the pressure drop will be greater.
So actually, with this restrictions, with well defined fluid density, velocity, pressure and flow maybe we get a constant pressure and flow at all the bearings. But if we go a bit loose on the clearances,that increase flow (useful for cooling them) we loose the equilibrium, so the unrestricted bearing get more flow that the others. Same increasing pressure (that increase also flow) or density of the oil...
So, the restriction will work well only on a well defined set of conditions. When we change some of this variables, why risk to get less pressure/flow than we want at some of the bearings due to this restrictions?
I think that on a well built motor, pressure will be increased at the 10psi/1000rpm rule and the bearing clearaces goes on the large side (no one wants a spun rearing...).
Wa have changed a bit the variables....

But also, why i haven't seen this type of restrictions in other engines that i've dismantled (mainly fiat/vauxhall)? Quite strange....

Or i'm missing something?
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Old 05-10-2010, 03:48 AM   #4
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Uhm, someone, please, have a dismantled engine block to actually measure this restrictions? They can be measured with some drill bits...
Really thanks!
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Old 05-10-2010, 05:45 AM   #5
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They are not a restriction compared to the bearing itself.
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Old 05-10-2010, 05:57 AM   #6
masterx81
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Yes, i've tought the same identical thing (and i've drilled them straight through), but... Why subaru have added them?
An other user here have reported that only removing #1 and #5 restrictions have destroyed the #2 and #3 rod bearings (really thank to him for sharing!!!).
The #1 and #5 main bearing are feeding only one rod bearing (#1 and #4), but the #3 main bearing is feeding 2 rod bearings.
This restrictions are here for lower a bit the flow to the less important bearings for have a bit more flow on the ones that need more flow.
So, actually removing them can increase flow on the bearings, but the most important bearing (#3) it's getting less flow...

Now i'm quite tempted to reapply the restrictions....

In the recent days are popped up 3 thread over here on the subaru oiling system, either can worth a read
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Old 06-06-2010, 06:51 PM   #7
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Still measurements of a closed deck block... Thanks!
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Old 10-29-2017, 11:40 AM   #8
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Default Verifying oil passages and orifice sizes in EJ25X cases

The following is from a different post in the "Oil Gallery Porting Thread", dated 3-12-17. I believe this verifies everything said by masterx81.
My question for anyone seeing this added to the old thread is How might I change the passage sizing now that I have a Manley "Direct Shot" crankshaft to work with? With oil coming to main bearings 2 and 4 from both directions (everything inside the Manley crank seems interconnected) not just the single passages off the galleries, it seems like they should be modified. Here is the gist of my other post:

EJ25 Series oiling system design and modification notes:
I am going to speak to the EJ25 engine because it's what I know. I want to make the caveat that the enlargements are untested for the moment. A lot of what I'm doing will be applicable to other, earlier engines, like the 2.0.
The majority of passages and orifices in the case do not exceed 13mm inside diameter (ID). Almost all passages in the case halves are cast-in using tapered core pins. Passages from the oil pump to oil filter and the return barely exceed 13mm and neck down to 12MM ID. Once oil reaches its highest point in the right-hand side of the case and branches off at 90° angles to the main oil galleries it is reduced to 12mm and tapers down to approximately 8mm at the end of the galleries. As the runners go from the left and right galleries to the heads they taper from 12mm to 7mm.
The single oil feed into the head's galleries is 6mm ID. Internally the heads are drilled to 8mm ID. The external feed tubes for the AVCS Control Valve is 6.5mm ID (8mm OD). There is a large reduction to 2 mm ID at the right, rear head banjo (where oil comes out of the head for feeding the turbo and the AVCS, *if you have the late model heads.

Other sizes of importance and summary:
Oil Pump feed to filter: tapered from 16mm to 12mm ID
Oil filter to upper galleries: this passage tapers from 12mm to 14mm ID and reduces down to 10mm as it transitions horizontally to the left side of the case.
Left side case oil gallery only goes half way to the rear of the case (tapers from 13mm to 8mm ID)
Right side case oil gallery (tapers from 13mm to 8mm ID, from each end of the case)
Turbo CHRA (bearing cartridge) Oil Feed (late model heads): 2mm ID*
Note: on many turbos there is another reduced ID orifice fitting to which you connect the SS braided hose.
Right Head Oil Feed Line (tapers from 12mm to 7mm ID)
Left Head Oil Feed Line (tapers from 12mm to 7mm ID)
Heads entrance for oil: 6mm ID (drilled)
#5 Main bearing and rear thrust bearing (6mm ID feeds #4 rod journal through crankshaft journal without reduction)
#4 Cylinder, rod bearing feed line (from #5 main/thrust bearing through crankshaft)
#4 Main bearing oil feed line (feeds only this main bearing)
#4 Main bearing feed line diameter reduction (passage reduces from 6mm minimum inside diameter to a 3.5mm orifice, like #2 main)
#3 Main bearing feed line reduces to 7mm minimum ID (feeds both #2 & #3 rod bearings through this one crankshaft journal)
#2 Main bearing feed line, feeds only this bearing (6mm minimum inside diameter passage reduces down to a 3.5mm orifice)
#1 Main bearing, with reduction to 5.5mm diameter (feeds from/beginning at the front of the right gallery)
#1 Cylinder, Rod Bearing feeds from #1 Main Journal through crankshaft journal)
Crank main oil holes are 5.5mm and rod journal holes are 4.5mm.

Summary: I eliminated the tapers in the galleries and cast passages. I made them 14.3mm (9/16") on the right side gallery. On the left gallery I made it 14.3mm till I hit the feed for #2 Main Bearing. I reduced it to 13mm (1/2") for the balance of the distance to the #3 Main Bearing runner. Feeds from the oil pump to the filter and back to the vertical runner up to the galleries were all enlarged to 14.3mm. I drilled the cast runners so they were a consistent 7mm to the journal.
All bends were radiused and blended. Feed runners to the heads were opened to 13mm ID. The receiving orifice in the head was radiused and tapered to be funnel-like.
Until I am convinced that the #2 and #4 Main bearing orifices can be enlarged I will leave them alone.
All this work was done with the express intent of running an 11 or 12 mm oil pump that is ported and shimmed to achieve 85PSI hot, with bearing clearances of Mains .0015" and Rods .002". I will use what has worked in the past for me and that is -10AN hose and fittings going to an external cooler and remote, oversized racing filter. Since -10AN is nominally .480"ID or 12.2mm and galleries and primary passages reduce down to 8mm or 10mm in stock form, I feel I now have the hose and fittings as my bottleneck. -10AN has worked successfully for me in undrilled cases to 7,200 RPM and 395 AWDHP.
This latest full case mod is for an anticipated 8,000 RPM red line and up to 500 CHP or 400AWDHP. My pistons weight 530 grams (complete) and the Manley rods 592 grams. Together, this is 14% less than stock.
I can't see a problem with what I'm doing but I will again throw in the caveat that some of these enlargement mods are untested.


UPDATE: One engine builder said he does not touch the orifices in the passages of main bearing 2 and 4. He did say he did much the same as the things I have done for 400+ WHP engines and that it helps.

Last edited by Scargod; 10-30-2017 at 10:34 AM. Reason: corrected spelling of gallery/galleries!
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Old 10-30-2017, 04:54 AM   #9
masterx81
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I've not analyzed anymore this restrictions, leaving them as-is, as it's quite risky play with the, but in the time i've also tought that can be here only for limiting flow in case of bearing failure, so limiting the damage to the other bearings.

This:
main 1: 5.49mm
main 2: 3.46mm
main 3: 6.23mm
main 4: 3.47mm
main 5: 5.30mm

Are the restrictions in the galleries galleys before the bearings of an ej20 v2 1997 engine

Last edited by masterx81; 10-30-2017 at 09:36 AM.
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Old 10-30-2017, 09:20 AM   #10
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Quote:
Originally Posted by masterx81 View Post
Are the restrictions in the galleries before the bearings of an ej20 v2 1997 engine
It's galley
not gallery
it's not a museum
sorry, I know that's stupid but was driving me nuts.
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Old 10-30-2017, 09:35 AM   #11
masterx81
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Quote:
Originally Posted by rtv900 View Post
It's galley
not gallery
it's not a museum
sorry, I know that's stupid but was driving me nuts.
Sorry, edit immediately
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Old 10-30-2017, 10:29 AM   #12
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Quote:
Originally Posted by rtv900 View Post
It's galley
not gallery
it's not a museum
sorry, I know that's stupid but was driving me nuts.
He does pretty well for an Italian in Italy working with English... Really, you just need to take a deep breath and reflect.
Many, many say galley. Professionals say galley. It's just one letter wrong and the context is what's important.
I thought it was galley from a lot of technical articles I've read so I picked up on it. I have been wrong. Now I have to go back and correct all my postings.
I think this states the obvious very well: "No, That's Not A Kitchen In Your Engine".
From Autozone: Gallery - A passageway inside a wall or casing, such as for oil circulation.
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