Oil Pressure

[maka]

Hi all..

I think my oil pump may be getting a bit sick...

Is someone able to tell me where their gauge sits when the car is at operating temperature, but just idling...

Mine sits between the 0 and the next marker, which should be 2...

I think that is a bit low, but am unsure.. When the car is cold, oil pressure goes up almost to 8.. so thats ok.. When driving normally it still sits under the 2 marker, but i think i remember my old engine used to sit between the 2 and the 4....

Should I be worried?? The engine has just had new bearings etc put in it, and this engine has spun a bearing before.. didnt cross my mind to replace the pump when putting it together, but think i might have to do it..

And input would be great...

Thanks.

[NISZILA]

Mine never goes under 2. Also doesn't go as high as 8 either. It pretty much sticks between the two lines. At the high one when its cold and the low one when its warm.

[Wogan]

Are you using the stock gauge? .. they are known to be completely unreliable.. mine reads similar to what you describe, but i had the garage test it and my oil pressure is fine.

Definately worth looking into, but don't replace anything major just yet.. could just be the gauge.

[maka]

Thanks for the reply guys..

I thought it should stick between the 2 and the 8... thats how i remember it being on my old engine..

I am using a GTR dash.. but willl try the oil press gauge out of my gtst dash, to see what happens... Just in case that is the issue..

Thanks again..

[Hotrod]

Maka.

I am having the same problem with mine at the moment and when I had a service i asked them to check it out and they advised me that is was the sender that was faulty witch is a normal thing and a replacement would be about $300 (witch I think is a bit high)

but mine sits on the first line when it is warmed up at idle and just under the second line when driving.

If anyone can tell me what the cost for a sender is let me know.

Thanks.

Edited April 2, 2008 by Hotrod

[4drftn]

get on the highway after driving for a good 20-30 min and drive in top gear of course at 100km/h (as it takes a while to build pressure). your oil pressure should be close to 4. the closer to 4 the better, being either side of the for means too little pressure/oil thin may need changing or low (before you think of topping oil up CHECK dip stick! and to get a good reading leave the car sit for a good while)... or too much pressure/may have to much oil (but after car has been recently serviced pressure will be a little higher).

i dont think mods or anything will change it.

if you have any doubts and think it may be dodgy. get an aftermarket mechanical gauge like autometer etc. or see a mechanic

hope this helps

cheers 4drftn

[br3ndan]

I have the official numbers for oil pressure from the Service Manual for the R33. I printed it out... YES its very long but it was worth it as i can have it next to me when working on the car. Below are the numbers from Nissan Japan Service Manual.

RB20E:

Idle: 1.0

2000rpm: 3.8

6000rpm: 4.8

RB25DE:

Idle: 1.0

2000rpm: 3.3

6000rpm: 5.3

RB25DET:

Idle: 1.1

2000rpm: 3.5

6000rpm: 5.6

RB26DETT:

Idle: 1.5

2000rpm: 3.0

6000rpm: 4.6

*Note these are pressures after engine has reached operating tempreture and its based on 7.5 - 30 oil. Obviously if you use different oil then to that, pressures will vary.

Edited April 2, 2008 by br3ndan

[tm_r33]

i will remember those figures br3ndan...

maka, the stock gauges aren't very accurate in my experience

[maka]

Thanks guys...

I drove the car around for a while last night, and monitored the pressure... It was really weird... Went from about half way between the 0 and the first line, to just under the first line... (thats where I think it is meant to me) then when driving on the freeway between the first line and the 4.. On the freeway at 100kmh.. SO I was kinda happier.. But then when leaving the car for a few hours, and starting to drive again, it was under the first line again.. even whilst on the freeway.. so i let it putt along at 80kmh, till it rose to between the 2 and the 4... SO yeah will replace the sender tonight.. as I have a spare one... And I'll also replace the dash, cause I have a spare one of those too... Will let you guys know, so if anyone has the same issue.. they can sort it out too... I'm replacing my radiator soon as well, so might just pull that pump out as well, and put a new one in there....

Thanks for the support guys.. much appreciated..

[bubba]

Don't bother replacing any of the stock stuff, get an aftermarket oil pressure gauge.

My stock sender/gauge reads fine (~8 on cold start) but after a bit of driving it barely reads over 0 and this is also very inconsistant.

However all the readings on my a/m gauge are good (I won't bother giving you readings as I'm running an N1 oil pump).

[bubba]

Oh and replacing oil pump isn't an easy job, it is possible to do it in the car but it's a MAJOR fk around, you need an engine brace to hold the engine from the top and then drop the whole subframe off, sump off, pistons off, crank out. Oh gearbox has to come out and clutch/flywheel off before you can get the crank out. Really, it's a whole motor out job.

Edited April 3, 2008 by bubba

[maka]

Oh really.. I didnt think it was that difficult... I ordered a N1 pump for my new engine too... but wasnt gonna put that in here... Ws just gonna put another standard one it, with a new seal and stiff...

I didnt think that I would need to pull the crank out etc.. I mean it is just a reverse of what I did when putting this motor together... see attached image, that was all on the engine when it was getting built, folllowed by the main crank cradle... but the pump did not go till all that was done....

I thought if i took off the belts, and the front main pully.. then took off the timing belt, then gear... it should be there and accessible....

I will have a look on my spare motor... Before I do anything anyways..

But before I start messin with that, I'll make sure its not just the pressure sender, or the gauge...

Thanks for the input though

[bubba]

Hmm you could possibly do it that way but I'm pretty sure at least the sump has to come off..

[maka]

Yeah always a good idea to take it off, just in case it ends up leaking cause of oil sealant on the block. to stop the sump from leaking..

Will change the gauge, and sender and see what it comes up with..

Cheers for the help,

[Steve]

couple of things:

After you change your oil, it will slowly start to degrade and loose viscosity AND pressure will drop

Different oils break down at different rates

Different driving conditions cause oils to break down at different rates

Different weights of oil will cause different pressure

Different oil filters can cause different oil pressure

Rather than rushing out and changing your oil pump, change your oil, use a good quality 15W50 (I recommend MOTUL) and see what happens. If you are still concerned, take your car into a workshop and get them to check your oil pressure

As mentioned above, the stock guage is not accurate but can work well as a guide

Edited April 4, 2008 by Steve

[bubba]

I know people dis the mechanical gauges but if you're smart about routing that little tube (put some small vaccum hose over it and don't put it anywhere it might rub) then they're fine, I would suggest getting one of those as opposed to screwing around with the stock sender/gauge.

[maka]

Cool...

I think I'll see if i can get a gauge somewhere....

Hmm so you would recommend the mechanical oil filled gauge?? Not the electronics ones with a sender???

I am currently using Mobil 1 5w 40...

and i only changed it on sat...

I will see what happens with it.

[Steve]

There is your problem right there

Mobil 1 5W40 is way too light for an RB, low oil pressure is just one symptom, you are probably also getting massive blow by - I almost filled a catch can in a couple of laps at Mallala, it seriously should never go in an RB

[br3ndan]

How is it to light?

5W is only the cold weight... and will only be light while the engine is cold.

Once it heats up, the hot weight 40 is sutiable for the Rb25. As nissan Reccomends hot weight of 30.

Maybe it will be different for you, as it seems that you use your car for track.. meaning the car will be pushed hard. But for Street i see no problem with that oil.

Edited April 4, 2008 by br3ndan

[Munkyb0y]

i have to agree that 5w40 wouldnt be too light

i've been using 7.5w30 and my oil pressure is fine (street use)