allenms240

Hey there guys,
I am having a little t rouble with some oil pressure on a rebuilt sr20det.
I rebuilt it and got about 400miles on it currently. After initial warm up, the oil was changed, and again after 50miles. The oil in there now has 350miles on it. The other day I went ahead a installed my manual boost controller and have finally been boosting the motor. The other night I noticed that after boosting hard, the oil pressure was pretty low. I was running about 20psi at 2krpm and about 9psi at idle. This was the first time it has run this low, up until now I had acceptable values. The gauge sender is an electric GReddy unit so I don't think that is the problem. The next morning I started the car and was reading the usual 80ish psi for cold start.
The oil pump was replaced (bought of a user who has about 500miles on it from new), the oil sump o ring was replaced in the rebuild, and an ISIS oil pan is on the motor, so I don't think it is a problem with the sump.

Could it be this conventional oil is breaking down early because of the heat the motor is causing? I am using 10w-30 valvoline conventional. In a few days the amsoil 10w-30 will be here and that is the synthetic I will be using.

Any ideas?

EDIT:
I changed the oil today to Amsoil 10w-30 and slapped on a new oil filter. I went to get some food, the car warmed up, all pressures looked good. After I left the food joint, the oil pressure was as it was before, it's low and it's worrying me. I got to school and shut the car off and waited for ten minutes. I then started the car and the oil pressure was fine. I was reading acceptable oil pressures. I'm sure that if I leave the car on for over a minute though, the pressure will drop. So, what could be causing this low oil pressure? Need some ideas fast because it's my daily driver.

Allen

allenms240

I just tested with an analog gauge (test kit) and getting the same results. So somewhere there is a blown seal or something. Any ideas?

AS240

is it a oem nissan oil pump or a ebay knockoff pump?

allenms240

I assume its an OEM one.
I wasn't aware theyre were knockoff ones. I will go check it out.

AS240

yeah you can get them from ebay. my friend bought a brand new one for his ka when he refreshed it and it did the same thing. oil press. was 8-10psi idling.
what are the oil pressure per rpm specs for a sr20?
example:
15psi @ 800rpm
30psi @ 2000rpm
etc...

allenms240

For an sr, it should me
11psi @ 900
46-54 @ 3200

I am getting roughly
9-10 @ 900
30 @3200

Also, when revving, the motor's pressure doesn't increase nearly as much as it should or used to in the 400 miles it's been driven.

I took a look at the pump and it sure looks OEM nissan.

My current plan is to gather where there are o rings or gaskets in the oil system and replace them in one day. So far I have:
oil strainer o ring
Oil pump/block o ring
2 o ring/washers on the filter assembly

Are there any more you can think of?

AS240

eh i'm not sure about an sr, i've never really torn into one. can you find a part number on the pump? or a nissan hamburger

allenms240

Confirmed, there is a Nissan logo.
Anyone else know any more info?

Dorifto Machine

Did you perform a leak down test ?

allenms240

Wouldn't a leak down test tell me where my external leaks are? How would I be able to do a leakdown test on just the oil system? Thanks for this suggestion, I will definitely give it a shot.

Synergy

I think they are curious to see if its a cylinder/HG/ring/internal issue.... Hence leakdown. It was rebuilt 400 miles ago so its not like this motor has been run for years and after changing the oil pump these are your issues.... Sounds like the oil pump is NOT your issue TBH.

wangan_cruiser

First thing i would check is the oil pick up. There is a gasket there. Did u happen u hit your oil pan? Any dents? The oil redtop pick up are prone on disconnecting due to vibration. I had mine weld reinforced then i eventually swapped it with an s14 pick up for better flow

allenms240

I will check the oil pickup, but nothing has been dented since its been on the road.


Synergy, should I go ahead and do a leak down test and see what the results are. I am looking for a loss in pressure that the block is holding, correct? Which COULD tell me if there is an internal leak. I checked the spark plugs and they check out (no oil), so does the oil (no water in it).

fliprayzin240sx

You said you're running an ISIS oil pan, since its a knock off pan, there might be a chance that the sump is sitting on the pan. Not 100% sure how you could check for this on a cast aluminum pan but I've heard of somebody having this issue with a Freddy oil pan.

Also, since its a fresh rebuilt engine, I'd check to see if you got any lose RTV that got into the pan and sucked up into the sump wire filter.

But as far as me being a prick, why the fuck would you go thru the trouble of rebuilding an engine and decide to use a used oil pump? I'm sorry, but take everything people who are trying to sell me something, with a grain of salt. They can swear up and down that they only used it for 500 miles but alot of bullshit flag would have popped up in my head. Why would an engine be parted out at 500 miles?!?! Always buy a brand new OEM pump from the dealer or a reputable shop like Phase2. The best part is that the OEM pump on these cars sucks enough, I can only imagine how much crappier a knock off pump would be.

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allenms240

I will check all that you have suggested.
I bought several items from this user that were described as almost new, just like the pan. They all looked new to me so no flags went up. Yeah he could have spend a shitload of time cleaning them just to make some money, but I doubt it.

Thank you for the suggestions kind sir.

fliprayzin240sx

Well, hope for the best...inspect the head and check the cams for scarring to make sure oil is making it all the way to the head. Also, run a thicker oil...even 10-40W can be too thin for these cars. I usually run 15-50W Mobil-1.

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Synergy

I built my block 6k later destroyed. RTV in the oil pickup. Im just saying to do a leakdown really to just make sure. I like to start on the inside and work out on these types of random weird issues with either burning oil or losing it or oil pressures


Also as an indicator I had low compression in 2 cylinders. a Leakdown will just give you some insight of how big of a problem this really is... It seems heat related.

Synergy

Whats your turbo return look like.... How are the angles. Oil turns to foam after leaving the turbo idk how you have it setup. It could be getting stuck in the drain. since its only started happening with more boost...

allenms240

Will do. I mean the motor sounds fine and still purs. I guess it could be loose debris in the oil sump filter. I will find out next week when the seals come in
Can you think of any other seals I should replace while I'm I'm there?

allenms240

Turbo return just has a hose from the drain to the block, there is almost no angle in the line.

allenms240

I will do a leak down test. Hopefully autozone has the rental for it.

I'm really only finding the cylinder leak down tester, is this what you were talking about? Is that the same as the compression tests?

Synergy

Thats all Id do... my car ran fine too... It ran so well I took it to the track lol. and it blew up. It dynoed and ran fine then eventually killed itself.

who built the motor?

allenms240

I built the motor. I'll check for loose rtv but I'm sure I didn't over-apply it. Only one way to find out. That. And a compression test.

allenms240

Anddddd...
It was the sump o-ring!!!




Or so I hope. I pulled everything off (crossmember, both oil pans, and about to proceed to the oil pump. I am going to go ahead and replace it for good measure.

So happy I found it.

Now I only have a problem with oil in cylinder three I need to figure out.