Ka24det oil cooler, really want to figure this out

[stuckonfresh]

Hello ladies and gentlemen. The engine's oil pressure is fine w/o oil cooler. With the oilcooler installed the idle oil pressure drops to as low as 8-9 psi, but the oil pressure operates under normal pressures as RPMs increase past the idle RPM.

The engine is a Ka24de(t) with:
-stock beltdriven oil pump
-stock oil pan and sump pickup (new gasket)
-journal bearing precision turbo (-4AN feed line, -8AN drainline)
-"T" fitting for oil feed line (stealthmode performance); where stock oil pressure sensor was threaded in under oil filter
-AEM 1-150psi electronic oil pressure guage; plumbed into the end of the T fitting
- oil feed line plumbed out of the side of the T fitting

*Earl's 19 row oil cooler; mounted in the inverted position with fittings on the bottom
*Greddy/GREX oil filter sandwich thermostat w/ -10AN fittings coming out of the 45 degree position ports on the sandwich ( the straight out ports were blocked with provided hardware; positioned so that the ports face the firewall.
*x2 45 degree swivel fittings from sandwich to tubing
*-10AN stainless lines from cooler to thermostat sandwich; W/ 120 deg and three 60 degree swivel fittings. (swivel fittings by Earl's).

Without the cooler and thermostat:
idle cold @ about 1K= (26-27)
idle warm @ about 950-1K=(13-14) then up to (17-18)

With the cooler and thermostat:
idle cold @ 1k= (26-27)
idle warm @ 950-1K = (10-11) sometimes as low as (8-9)
WOT @5500= 76; @3K=60

What am I doing wrong?! Any ideas? I've started looking at physics principles in the Fluid mechanics field and stuff like Bernoulli's Principle, but this still doesnt make sense to me because even though the oil is going to a larger diameter passageway (tube), it still returns to the same size passageway in the engine (and through the oil squirters). Any help would be greatly appreciated, thanks in advance :)

[240sxfan6882]

Hello ladies and gentlemen. The engine's oil pressure is fine w/o oil cooler. With the oilcooler installed the idle oil pressure drops to as low as 8-9 psi, but the oil pressure operates under normal pressures as RPMs increase past the idle RPM.

The engine is a Ka24de(t) with:
-stock beltdriven oil pump
-stock oil pan and sump pickup (new gasket)
-journal bearing precision turbo (-4AN feed line, -8AN drainline)
-"T" fitting for oil feed line (stealthmode performance); where stock oil pressure sensor was threaded in under oil filter
-AEM 1-150psi electronic oil pressure guage; plumbed into the end of the T fitting
- oil feed line plumbed out of the side of the T fitting

*Earl's 19 row oil cooler; mounted in the inverted position with fittings on the bottom
*Greddy/GREX oil filter sandwich thermostat w/ -10AN fittings coming out of the 45 degree position ports on the sandwich ( the straight out ports were blocked with provided hardware; positioned so that the ports face the firewall.
*x2 45 degree swivel fittings from sandwich to tubing
*-10AN stainless lines from cooler to thermostat sandwich; W/ 120 deg and three 60 degree swivel fittings. (swivel fittings by Earl's).

Without the cooler and thermostat:
idle cold @ about 1K= (26-27)
idle warm @ about 950-1K=(13-14) then up to (17-18)

With the cooler and thermostat:
idle cold @ 1k= (26-27)
idle warm @ 950-1K = (10-11) sometimes as low as (8-9)
WOT @5500= 76; @3K=60

What am I doing wrong?! Any ideas? I've started looking at physics principles in the Fluid mechanics field and stuff like Bernoulli's Principle, but this still doesnt make sense to me because even though the oil is going to a larger diameter passageway (tube), it still returns to the same size passageway in the engine (and through the oil squirters). Any help would be greatly appreciated, thanks in advance :)

Your oil pressures in PSI are really low.
Dead cold start I get 50-51 PSI on 10-30 oil, and 54psi or so with 15/40
I can't remember off the top of my head what I get for operating temperature... but it's along the lines of 17psi or so on 10-30 oil.

Your oil pressures seem really low for some reason: have you replaced the pump? Have you made sure that the little O ring that goes between the oil pump and the block is installed?

[hotlavaflow]

I agree my oil pressure, 10w30, is higher than his^^^

[stuckonfresh]

I'm glad you guys said that, I was beginning to think I was the only one who thought the oil pressure was low. To the best of my knowledge, the oil pump has not been replaced. This engine is currently on its 2nd rebuild, so it is a possibility that that o ring you mentioned was not replaced with a new one or maybe not put in at all.

Before I pull off the front cover, are there any other signs I should check for for a bad oil pump?

*Oh and my apologies, I for got to mention that, the oil is 10w30 Castrol GTX.

[Mikester]

* mounted in the inverted position with fittings on the bottom


That is your problem.

See this link (http://www.utxchange.com/faq/services/air-to-oil-cooler-installation-guidelines/)

Long story short, you are working against physics by mounting it upside down. There will always be a slight pressure drop due to adding additional fluid & plumbing to the system... Mounting it upside down not only exacerbates that; but also hinders the cooling capability.

[stuckonfresh]

Thanks for the link and the short explanation. That all makes sense. The Cyber Evo from the time attack series has its oil cooler mounted sideways (ports on left side and most every other car has their coolers mounted with the ports on top.

The reason I mounted the cooler like I did was because of clearance issues. Basically, without welding anything I was able to position the cooler in a way that it cleared the cold pipe coming from the front mount, with the downward facing fittings of the oil cooler on either side of the pipe.

I thought about putting in a bleeder bolt at the top of the cooler and some check valves, but even that wouldnt make it better; especially with a thermostat that slowly opens and closes.

So assuming there is air at the top of the cooler (which is most likely the case), once the thermostat opens there is an initial drop in pressure, due to the oil entering added oil passages (tubing and cooler). Then there is probably an air pocket at the top of the oil cooler, which is preventing the oil cooler "system" from completely filling and achieving normal oil pressures. The added oil pressure at WOT most likely compresses this airpocket enough to achieve "normal" oil pressures at WOT.

Does this sound correct? After I reorient the cooler, should I step the hoses and fittings down to an -8AN? or do guys think it would be okay to retain the -10AN with a stock oil pump?

[Taniguchi_Is_#1]

Oil Cooler Mounted Upside Down (http://www.ziptied.com/forums/index.php?topic=22475.0)

^^ counter argument.

Did you properly bleed the cooler before mounting in its final position?

[stuckonfresh]

Thanks for the link. I've been trying to convice myself with similar arguments that other people have mounted it upside down and have had no problems with their oil pressure; I think there was even a picture of the GST/Hankook 2door subaru Global time attack podium winning car in Modified mag with its front bumper off, showing a cooler of something, mounted upsidedown. *edit , found a pic*
http://s8.postimg.org/ep6xj3pb9/image.jpg

Maybe it depends on the engine itself? (oil squirters, oil passages?)

I dont think I purged it correctly, I just filled the oil cooler with oil rightside up, attached both hoses to it, attached one end to the thermostat sandwich and then poured oil into the other side of the hose and attached that side.Then I started the engine and let it warm up, listened for the thermostat to open and when both hoses and cooler were warm to the touch, I took it out for a drive.

Could the thermostat's positioning (ports facing the firewall instead pf the ground) have anything to do with the decrease in oil pressure?

[redline racer510]

I have my oil cooler on my rb25 mounted upside down for nearly 2 years and I have yet to encounter any problems. I didn't bleed it or purge it or anything. I just took one of the hoses off and poured oil till it filled up then installed the the line back into the oil block adapter.(my oil block has built in thermostat) the picture above shows how i have my oil ccooler mounted

[Mikester]

For the record, I'm not an expert... Found that on Google when I was finalizing how I should mount my cooler a few mos back. Probably shouldn't have stated the issue with such certainty. I mounted it that way and have right about 17-20 psi at idle and 5-6 bars at WOT w stock pickup & original pump/cover. Granted mine is an SR but I thought maybe it'd be worth repositioning it and seeing if it improves vs. tearing the pump apart. I have the very same GREX block mounted upright as well ...

65847

Just trying to help.

[hellion240sx]

Oil Cooler Mounted Upside Down (http://www.ziptied.com/forums/index.php?topic=22475.0)

^^ counter argument.

Did you properly bleed the cooler before mounting in its final position?

so what this says is:

An oil-to-air cooler should not be installed with the ports at the bottom of the cooler. Ports located at the bottom of the cooler can create venting and filling problems. With bottom ported coolers in low oil flow conditions, the core may not become full and the hot oil is allowed to pass through only a portion of the core.

the two pictures are the correct way, correct?

[hobbs]

Thanks for the link. I've been trying to convice myself with similar arguments that other people have mounted it upside down and have had no problems with their oil pressure; I think there was even a picture of the GST/Hankook 2door subaru Global time attack podium winning car in Modified mag with its front bumper off, showing a cooler of something, mounted upsidedown.

Just need to point this out, you're going to compare a fully worked over race motor to your 25 year old stock nissan motor as justification as to why you have setup your oil cooler improperly?


:werd:

[stuckonfresh]

redline racer510- Thanks for sharing; so basically same setup, but different motor? Do you remember what size hoses you are running to your cooler by any chance?

Mikester- I appreciate your honesty, I'm not an expert either, but i'm hoping with your help and everyone else on here we can try to find some reason why the oil cooler orientation works well on some engines and not on others. Are you also using -10AN lines for your thermostat and cooler setup?

hellion240sx- yes, I believe the pictures on the page in the link are the correct ways of mounting the cooler; the wording is a little wierd in the paragraph above the pictures on that page; I believe thats what they meant though. I had to read twice.

hobbs- I suppose I can only hope that mechanic who decided to mount the cooler on that race car knew what he or she was doing.

[Mikester]

Yes, my lines are all -10AN.

Here is the cooler:

http://farm4.staticflickr.com/3784/8993507031_6c812e3897_c_d.jpg

Feed is on the left (observer's right, by upper horn), return on the right...

Here is my thought process...

On brakes, why is the bleeder port at the top? Simple- Because if the bleeder were at the bottom, you'd never get all the air out of the system. An oil cooler is the same principle... Mounted upside down, how exactly do you get all the air out when it will just float to the top of the cooler and stay there?

Mounted with the fittings on the side w/feed at the bottom & return on top, it forces any air in the system out the top and back into the pan. Mounted upright, the very same thing happens. My guess with that full-race Subie in the pic is that the oil cooler is a one-way design so that any bubbles are forced out the return regardless of orientation... or there are additional components in the oil distribution system that make up for it... or both.

Much like bleeding brakes... I wonder if you are experiencing such a drop in pressures due to air being stuck in the cooler with no place to go. Just a hunch.

[redline racer510]

My lines are all -10 (greddy sandwich plate with built in thermostat, setrab 10 row oil cooler) and if you think about it the flow pattern is the same whether you have it mounted upright or upside down, the oil has to travel down than back up or up and than back down so i don't think it should matter plus air should automatically be bled as soon as your engine starts to warm up or at least with a little driving around.

[Mikester]

^^I slightly disagree. My theory is still that changing the orientation will help get his pressures up. Mounted upright/sideways, the oil is forced thru the entire core on its way in/out. Depending on the internal design, it could be filling up with air.

I did some checking yesterday and this morning- With OG stock pump/gear and standard S13 pickup & large oil pan/cooler, my pressure at idle (warm) is about 1.2bar (17psi) and about 3bar (44psi) at 3,000rpm cruise on the freeway. I use 10W30 oil and right now, ambient temp is in the single digits/low teens. Again, being an SR; it could be apples and oranges... but hopefully it helps you get an idea.

Adding the extra fluid involved with a cooling system 'should' result in a pressure drop- but not like you are experiencing. If I were near you, I'd be happy to help you reorient the cooler just to see what happens. Good luck~

[stuckonfresh]

redline racer510- Thanks for sharing that info. I was actually thinking the same thing because after everything was warmed up wih the cooler installed and the thermostat open, the oil pressures were relatively normal (to the best of my knowledge), within about 2psi of what pressures were w/o the cooler. Plus, unlike the powersteering system or brake system the fluid in the oil system is constantly flowing in one direction wih pressure changes. I'm thinking I may have to flip the cooler, just to test the effects, so we can take that factor out of the equation.

Mikester- The air pocket trap at the top of the cooler you described makes sense. Generally, gas is more compressible than liquids, so... despite the oil pump putting out the correct pressure and volume, the air pocket could be compressing and acting as a buffer to reduce the oil pressure. Thanks for sharing that info about your oil pressures too, the more info the better, even if its a different engine its still relevant to the oil pressures with an oil cooler.

Yeah that would be great if you guys were near me, but Im assuming you guys will not be near philly anytime soon. Well with the info we have so far, it seems as if the -10an lines should not make a difference. Searching around, I found some info on another forum too where -10an lines to a setrab style oil cooler were used without a problem.
LINK:
Oil Pump Pressure for KA24DE - to Shim or Not to Shim?? - IT.com Forums (http://www.improvedtouring.com/forums/showthread.php?t=16611)

They also talk about, in general, 10psi increase for every 1000 rpm. They mention larger bearing clearances for a cause of low oil pressure and shimming the oil pump. For now, I'm just going to focus on the oil cooler system. This "polar vortex" weather nonsense in the eastcoast is killin my motivation to work in the garage, but I'm going to plan on running a pressure test with the oil cooler fittings on top soon; maybe this weekend if it doesnt snow again. I'll report back with my findings, in the meantime keep the ideas coming, I'm listening.

[Mikester]

^^LOL^^ Yea Philly is the exact WRONG direction I'd be headed anytime soon. However, I may mull this over a bit over a beer while sunning on Huntington Beach :D

[redline racer510]

Yea I think I will be staying in Cali lol. Try flipping it around and using some cheap bracket or zip tie temporarily, I doubt your oil pressure is gonna change though. Keep us posted.

[stuckonfresh]

.
haha, nice!

Well You guys are not missing out on too much here on the eastcoast, it was 10 deg F. here last night and it snowed!

The temporary bracket for the cooler is a good idea. I'm thinking I may have to wait until it gets a little warmer out. I was working on our SUV yesterday and my fingers felt like they were going to fall off.

Thanks again for the input so far, I'll keep you guys posted.