Results 1 to 11 of 11

Thread: What oil pressure with Newly Rebuilt 4y engine

  1. #1
    Van Fan
    My Van(s):
    1986 LE
    Join Date
    Aug 2017
    Location
    Florida
    Posts
    67
    Rep Power
    1

    What oil pressure with Newly Rebuilt 4y engine

    Just had my 4y engine rebuilt. Before it went in my oil pressure was in the middle of the normal pressure markers at 3000rpm and about 1/4 up from the bottom when idling. Now with the new rebuilt engine it is at the bottom line at 3000rpm and only 1/8 up from bottom. So it is time to put a gauge on it. Anyone know what these numbers should be with a newly rebuilt engine?

    MT

  2. #2
    Van Addict
    My Van(s):
    1988 4WD LE auto dual range t-case 1988 4WD LE auto(the donut van)
    Join Date
    Aug 2012
    Location
    Tacoma, Wa
    Posts
    489
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Was the sending unit replaced with the engine rebuild? It's not really an apples to apples comparison if it's a different sending unit. I found aftermarket sending units to be of poor quality of late with their resistance frequently being out of spec from OE. As far as correct pressure, the manual calls for 4.3 psi or more at idle and 36-71 psi at 3000rpm both specs with the engine at normal operating temperature.

  3. #3
    Van Fan
    My Van(s):
    1986 LE
    Join Date
    Aug 2017
    Location
    Florida
    Posts
    67
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Quote Originally Posted by originalkwyjibo View Post
    Was the sending unit replaced with the engine rebuild? It's not really an apples to apples comparison if it's a different sending unit. I found aftermarket sending units to be of poor quality of late with their resistance frequently being out of spec from OE. As far as correct pressure, the manual calls for 4.3 psi or more at idle and 36-71 psi at 3000rpm both specs with the engine at normal operating temperature.

    IN the manual? Crap, did not see it. Thank you

  4. #4
    Van Fan
    My Van(s):
    1986 LE
    Join Date
    Aug 2017
    Location
    Florida
    Posts
    67
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Another thought before I take the measurement and potentially screaming at the Machine Shop.
    I know Tim had said in one of the oil pressure threads that the minimum we should see at hot idle was about 12 PSI.

    I guess my question is what is the norm folks would see on a newly rebuilt engine. I think his point was 12PSI was a minimum after many miles like 200K.

    Assuming the pressure reduces over time I would have to think that the typical pressure on a newly rebuilt would be higher allowing it go another 200K before it bottoms out at 12PSI again.

    Just want to make sure this guy did not screw me up with this.

    Anyone have any thoughts on this?

    Thanks for the response thus far.
    MT

  5. #5
    Van Obsessed
    My Van(s):
    88 4WD DLX 5spd
    Join Date
    Oct 2010
    Location
    Ontario, Canada
    Posts
    607
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    I think you should out a gauge on it and find out what reality is.
    As long as your within specs with what the factory says all should be good.

    Factory sensors are notoriously inaccurate, granted the change from before to now is extreme and I would have expected higher numbers from a tighter motor but until you know what the reality is theres no point getting upset ahead of time.
    It might just be time for a new sender

  6. #6
    Van Fan
    My Van(s):
    1986 LE
    Join Date
    Aug 2017
    Location
    Florida
    Posts
    67
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Quote Originally Posted by Burntboot View Post
    I think you should out a gauge on it and find out what reality is.
    As long as your within specs with what the factory says all should be good.

    Factory sensors are notoriously inaccurate, granted the change from before to now is extreme and I would have expected higher numbers from a tighter motor but until you know what the reality is theres no point getting upset ahead of time.
    It might just be time for a new sender


    My thoughts exactly BB. I remember your suggestions when looking for a good shop and I took every precaution.

    I will get the real numbers and let you know.

    Thanks again

  7. #7
    Van Fan VanCo's Avatar
    My Van(s):
    1987 Toyota Van LE 4x4 5spd, on 30x9.50R15s, boosted to 7PSI
    Join Date
    Mar 2017
    Location
    Salt Lake City
    Posts
    78
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Before I rebuilt my engine it had low oil pressure. This was suspected based on the factory gauge, and verified using an oil pressure tester gauge set.

    After the rebuild the factory gauge was about where it was before the rebuild. Worried, I quickly checked it using the gauge set. It tested on the high side of normal per the FSM.

    I'm not sure if it is the gauge, or the sending unit. I never did any further diagnosis. What I can say, is that in my case, the factory gauge had the same/similar low readings with lower, and higher pressure. I'm not surprised, factory gauges are designed to make a very broad range, that an engine typically runs at, appear normal on the gauge. When they malfunction they do strange things.

  8. #8
    Van Fan
    My Van(s):
    1986 LE
    Join Date
    Aug 2017
    Location
    Florida
    Posts
    67
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Thanks VanCo:


    I am tending to think the same thing. I will know more when I get it measured. Lots of money spent only to get back to low pressure. You are probably right. I will report in when I know.

    MT

  9. #9
    Van Addict
    My Van(s):
    1988 4WD LE auto dual range t-case 1988 4WD LE auto(the donut van)
    Join Date
    Aug 2012
    Location
    Tacoma, Wa
    Posts
    489
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Quote Originally Posted by MyToy View Post
    IN the manual? Crap, did not see it. Thank you
    The information I quoted was found in the "Lubrication System" section of the FSM.

  10. #10
    Van Fan
    My Van(s):
    1986 LE
    Join Date
    Aug 2017
    Location
    Florida
    Posts
    67
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Hello everyone

    Just got the numbers in on the newly rebuilt 4Y from my 86 LE.

    They came back with a low pressure number when at operating temp of 22lbs.

    The pressure sender was in fact bad. Now it response respectively.
    So for any of you that are questioning your pressure and has not tested with gauge you may want to do that and/or replace the sender.

    I am happy now

  11. #11
    Moderator
    My Van(s):
    89' TownAce auto 87' 4x4 5spd LE
    Join Date
    Mar 2014
    Location
    SEATTLE, WA
    Posts
    1,365
    Rep Power
    1

    Re: What oil pressure with Newly Rebuilt 4y engine

    Oh very nice detective work, which pressure sender and part number did you end up using?

    Thank you

    JDM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •