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Keegster
01-17-2020, 07:48 PM
I just rebuilt my notchtop sr20det and it has low oil pressure. I had 10w-30 in it and it turned the oil pressure light on when it was warm and idling. I switched to 15w-50 and checked it with a gauge and it was at about 8 psi warm and a little under 1000rpm. It has an s14 pick up, oem pick up gasket, and oem o ring.

It has brand new ACL race bearings I double checked the bearing clearances and it had .0008 on 2 rods and .001 on the other 2, the fsm calls for .0008 to be the tightest. The main bearings had between .001-.0012 which is a little over what the fsm wants but nothing bad especially for 15w-50.

The oil pump isn't new but had very few miles and almost now scoring on the sides and its oem pump. It had a new oem filter for a 14 or 15 sr. All 5 squirtters are there and aren't broken. One valve is out of adjustment because I lost the shim and replaced it with a random one (I found it now).

The stock t28 has an aftermarket braided line with a restrictor at the end, the line is a unknown to me because the last owner bought it. The turbo drain is a custom made one by me to correct the angle on it and it has a double silicon hose on it. The motor sports teacher at my school was thinking the oil relief valve may have been stuck, and I took it apart moves freely. He now thinks some debris could have kept the valve open because the motor sat uncovered for a while, but I've cleaned it now.

The same issue plagued the last owner of this sr20. Does anyone have any ideas of what could be giving me low oil pressure before I put it back together on Tuesday? Is there anything I missed??

gaz_moose
01-18-2020, 01:57 AM
you could just fit a new oil pump (but not whole cover) and relief valve. to cross those off the list.

anthony_240
01-18-2020, 01:24 PM
Do you have an aftermarket oil pressure gauge? Have you verified low oil pressure in the oil galleys?


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S14rebuild
01-18-2020, 03:47 PM
Install a mechanic oil pressure guage first and confirm the low oil pressure first!

Keegster
01-19-2020, 06:01 PM
Yes I checked it with a gauge, I said that in the post, a true mechanical gauge. I checked it at the original oil pressure sensor hole.

RalliartRsX
01-19-2020, 06:56 PM
Did you install the o ring behind the oil pump?? Almost everyone I know who has taken off the oil pump always forgets the o ring. Without it, oil just bypasses the oil pump and cause the very condition you are seeing.

https://www.picclickimg.com/d/l400/pict/202247915167_/SR20DET-Oil-Pump-O-Ring-For-Nissan-SR20DE-SR20VE.jpg

Keegster
01-19-2020, 06:58 PM
Yes I put a brand new one on it

s13 @ fullboost
01-19-2020, 09:53 PM
Whats oil pressure cold? There is a good chance you have a bum pump. Do you notice any oil leaks? Pull your oil fill cap off & see if you can see your camshaft oil squirter's spraying.

Keegster
01-19-2020, 10:00 PM
I didn't check the pressure when it was cold, but the light would stay on too long when it was started. I did check the squirters and they were just dripping, not spraying. I soaked them and made sure all the holes were clear. I forgot to mention that the oil pressure will slowly fall, I can rev it and it will go to let's say 12 psi and then it would slowly fall to about 8 psi. I find it very weird. Why would a pump that's almost new be bad?

s13 @ fullboost
01-19-2020, 10:16 PM
I didn't check the pressure when it was cold, but the light would stay on too long when it was started. I did check the squirters and they were just dripping, not spraying. I soaked them and made sure all the holes were clear. I forgot to mention that the oil pressure will slowly fall, I can rev it and it will go to let's say 12 psi and then it would slowly fall to about 8 psi. I find it very weird. Why would a pump that's almost new be bad?

When you rev it up whats the highest you see the oil pressure go to? Sometimes brand new parts fail right out of the box. I am trying to find the common denominator. You did a rebuild? The same oil pump was used & now you still do not have oil pressure. If you put the O-ring then its possible that the oil pump gear has flaws from the machining process. Its not able to pump, especially when the oil heats up & thins out. Possibly due to clearance issues from manufacturing?

Keegster
01-19-2020, 10:57 PM
I have the bottom end apart to try to find the issue, and I never revved it when I had the gauge on it because I was afraid to. I can measure the pump versus a known good one before I put I back together. Nothing else comes to mind as why it could be low?

mechanicalmoron
01-19-2020, 11:04 PM
Is there an oil restrictor sandwiched between the head and block? Some cars have restrictors that manuals (and enthusiasts) don't really mention (or rather, is there a little cup in the head feed, that COULD have had a restrictor in it).

https://www.miataturbo.net/attachments/general-miata-chat-9/48760-where-get-fancy-oil-feed-like-one-f_cyht_53c_u77ts.jpg?dateline=1341944518

There's one google found me that says it's off a miata, I was imaging exactly that off a honda, everyone's got em.

Also, oil galley plugs leaking internally into the engine? Tensioner o-ring?

Since you mentioned it, I assume the pickup is of a different design, is it longer or does it have a different skirt design on the strainer, that's sitting on the bottom of the pan? Or is it an aftermarket pan?

I have a b18 that would sit with the light on for 30 seconds, but it didn't knock or anything so I let it ride a while - eventually I took a hammer to the dent in the pan and now she's instant.

*edit* This seems to have one (https://www.project200sx.com/technical-info/sr20-engine-differences/44-oil-feed-to-tensioner)

Keegster
01-19-2020, 11:07 PM
I believe that was there, I put the head on it 2 years ago. I pulled the pan off and took a hammer to it and it didn't fix the issue

s13 @ fullboost
01-19-2020, 11:43 PM
I just rebuilt my notchtop sr20det



The oil pump isn't new but had very few miles


The same issue plagued the last owner of this sr20

I believe that was there, I put the head on it 2 years ago.



Not trying to be a dick but I am honestly confused now?

Keegster
01-20-2020, 12:51 AM
I bought the motor 2 years ago disassembled. I got the rotating assembly together not long after I got it and just let it sit because I didn't need it. My ka spun a rod a few months ago and I finished the sr and put it in

s13 @ fullboost
01-20-2020, 01:50 AM
I bought the motor 2 years ago disassembled. I got the rotating assembly together not long after I got it and just let it sit because I didn't need it. My ka spun a rod a few months ago and I finished the sr and put it in

Ahhh okay now I am up to speed. Well I would carefully inspect all your oil passages. I highly suggest spending the 180 bucks & getting a new oil pump before re assembly. Just my two cents, I really hope you get it resolved. I know how frustrating things like this can be.

jedi03
01-21-2020, 09:34 AM
I had same issue with my SR I rebuilt...at idle when warm was low pressure...suspected just bad gauge or sending unit, verified had good flow during idle (face full of oil with valve cover off lol) disconnected the gauge and called it good...personally had all brand new parts and had measured all parts with assembly...prob could have shimmed the pump but let us know what you find!