oil pressure /oil cooler

[wild_maxx]

I have been doing research on an oil cooler setup for my ka24e-t. When the car starts up cold I have about 65 psi of oil pressure, when it warms up I get about 15 psi at idle and around 10 psi increase of pressure for every 1k rpm's ( 3k rpms = 30 psi of oil pressure) when @ operating temps.

Question... after driving on the highway for around an hour or so the oil pressure will start to go down just a little. say i'm at 3k rpms with 30 psi then hit the highway for a while and the pressure will go down to about 28 psi or so.

Would an oil cooler help solve this? I'm not sure if thats too low of pressure for cruising on the highway but it kinda scares me when I am cruising at 3k rpms.

The oil cooler setup will include a thermostat (180*) and an rx-7 oil cooler up front. Anyone have problems with just using rubber lines instead of the SS braided kind? I'm not going to do the filter relocation.

Another Question.. do sidemount turbo's increase the temps of the oil? My turbo is about 3" away from the block and I was wondering if the heat from the turbo would increase the oil temps which would make the oil thinner creating lower pressure?

[coolbone28]

what oil are you running? And whats the ambient temperature?

[wild_maxx]

10w30 non synthetic. Its a brand new engine with about 1500 miles on it so i'm still adding up the miles before I switch over to full synthetic.

[coolbone28]

I don't think that your oil would be getting so hot to make it that low. Stock oil pressure is 11psi at idle and 60-70 at 3,000rpm. I have my oil feed line running behind my motor and then along the side until it meets the turbo. So i have engine,turbo, and DP heat and still no problems. Usually when my car has been driven a long time my idle pressure is at 18 and while cruising at 3k it is usually around 50+psi (with 10w30). Are you running a mechanical Oil press. gauge? Maybe the line is kinked somewhere.

[wild_maxx]

its an electric autometer gauge and even when the motor was stock the oil pressure was around 30 psi at 3k rpm's when hot. I am going to drive it for a while then try to take an oil temp reading off the pan and get a close estimate of what my oil temps are at.

[coolbone28]

Is it possible that your stock oil pressure switch/sensor is not working correctly? I am assuming you are spliced into the stock sensor.

[wild_maxx]

No I have the autometer oil pressure sensor screw into the oil port for the stock sensor as well as my feed line for the turbo. The stock sensor is completely gone.

[NateDogg]

Did you install a new oil pump on the rebuild? On the DOHC, the manual calls for around 30psi at idle, 60-70psi at 3000rpm.

Sounds like you have low oil pressure...

[wild_maxx]

yeah its a new oil pump. I used a 280zx high flow oil pump to be exact. I guess i'll try another one and see if the pressure stays up after its hot. What should normal oil temps be around?

[coolbone28]

Did you install a new oil pump on the rebuild? On the DOHC, the manual calls for around 30psi at idle, 60-70psi at 3000rpm.

Sounds like you have low oil pressure...

actually 11+ psi is stock idle pressure per my 95 fsm and even with the sohc fsm.

wildmaxx, do you know what the pressure of the 280z oil pump is supposed to put out? any specs on it? i would just try a stock oil pump and see what happens. I highly doubt it's from your oil being too hot.

[coolbone28]

if you want to test the oil temp I believe that it should be around the 200*F mark. Maybe a little higher. Also it may be important to find out which oil the 280zx guys use. Since different cars use different grades of oil...mostly dependent on the abilities of the pump to push out certain weights of oil.

Just did a little searchin and it seems that the 280zx guys are using heavier stuff. you could try 20w30. (other oils mentioned in articles were 10w40 and even 20w50). Just tryin to get some ideas out there...
Modified by coolbone28 at 12:56 AM 3/5/2007

[wild_maxx]

I could use a thicker oil but that might just be a band-aid for a serious problem. I'll replace the pump and see how the new one performs. Are all you guys seriously getting 50-60 psi of oil pressure on a hot engine? say after driving it for an hour or so?

[wild_maxx]

Well I did more testing today to figure out the problem. My autometer electric oil pressure gauge is not correct... I hooked up a mechanical oil pressure gauge and was getting around 12 psi at idle hot and around 40 psi @ 3k rpms when it was hot. I added a shim to the oil pump to see how much that would bring it up... and it did about 5 psi or so. I guess i'll try a new pump and hope for the best.

This is hot engine cruising at 3k rpm'sThis is the mechanical pressure gauge at idle w/hot engineMech. gauge at 3k rpm's with car parked but this was after about 30 minutes of cooling offCold startup pressure

[Ligouri Rd]

Did you install a new oil pump on the rebuild? On the DOHC, the manual calls for around 30psi at idle, 60-70psi at 3000rpm.

Sounds like you have low oil pressure...

...Well I did more testing today to figure out the problem. My autometer electric oil pressure gauge is not correct...

Did you use any sealant on the oil pressure sender when installing it? The sender needs to have a solid ground with the engine to work correctly any sealant could be insulating the sender. Possibly you can attach a wire from the sender and then run that to a ground lug attached to the engine. Please forgive the zip ties.

[wild_maxx]

I did use thread sealant on them the first time. Then I removed it and the pressure was still off. I did not try to ground it to the block... but I already installed the mech. gauge and its working fine. I still low oil pressure (about 40 psi at 3k rpm's hot) but i'm not going to worry about it anymore... if it eats the bearings... its time to get a new motor.

I found this article and it said the general rule is about 10 psi for every 1k rpms.. so i'm not too worried about it.

http://www.geocities.com/pcwri....html