User Tag List

+ Reply to Thread
Results 1 to 7 of 7

Thread: Oil pressure advice

  1. #1
    Bodger

    Join Date
    Jul 2017
    Location
    Povegliano veronese
    Age
    27
    Posts
    133
    Thanks
    70
    Thanked 17 Times in 12 Posts

    Oil pressure advice

    I have a rebuilt pinto with new bottom end, new std crank bearings, only polished crank (not 0,25mm undersized), the polished diameter was 0,010mm under spec, I kept the original burman oil pump, inspected it before putting it back and it looked quite good. I have the oil radiator and 20w-50 mineral oil.

    I started the engine doing some 20 minute around 2-3k revs to help break in the new pistons, done it twice and now I have around 3,8bar (55psi) at cold start, and around 3,2bar (45psi) with the engine warm (don't have oil temperature sensor, but the water was at 90°).

    On friday I have a track sessions to properly break in the engine and then running it hot so I will have precise number regarding hot oil pressure.

    What I'm wondering is if I should be going with an higher pressure pump, or just try to keep it standard with new internals.
    Or if I can keep it like this, if those numbers are right, considering that this engine will be living on rally stages above 3-4k rpm.

    Thanks, Enea.

  2. #2
    Pit Crew Decade Plus User onecamohv's Avatar

    My 1st Project
    Join Date
    Jun 2012
    Location
    ireland
    Age
    38
    Posts
    1,155
    Thanks
    37
    Thanked 88 Times in 78 Posts

    Re: Oil pressure advice

    2 things - what was the measured bearing clearance? crank diameter gives nothing to go off.
    mains and big ends? doesnt say.
    this is really the main determining factor

    2nd thing, 90deg water also gives no indication of oil temp, it will take way longer if ever, at idle to get real temperature into the oil.

    55psi with cold 20w50 seems a bit on the low side, but is that just at idle speed? if so what rpm? what does it go up to if you raise the revs?

  3. The Following User Says Thank You to onecamohv For This Useful Post:


  4. #3
    Bodger

    Join Date
    Jul 2017
    Location
    Povegliano veronese
    Age
    27
    Posts
    133
    Thanks
    70
    Thanked 17 Times in 12 Posts

    Re: Oil pressure advice

    Quote Originally Posted by onecamohv View Post
    2 things - what was the measured bearing clearance? crank diameter gives nothing to go off.
    mains and big ends? doesnt say.
    this is really the main determining factor

    2nd thing, 90deg water also gives no indication of oil temp, it will take way longer if ever, at idle to get real temperature into the oil.

    55psi with cold 20w50 seems a bit on the low side, but is that just at idle speed? if so what rpm? what does it go up to if you raise the revs?
    1st, main bearing, 56,97mm, bearing clearence was told to be ok, didn't check it myself.
    2nd, i know it's not really indicative, but if the water is at 90deg for 15/20 minutes, oil can't be at 30, oil pipes were warm, real hot temperature and high rpms, I will get it on track.
    3d, yes at idle speed, 1000rpm. I didn't rev it above 3k.

    "a bit on the low side" is what I was interested in, thanks.
    Last edited by Enea; 15-11-2021 at 13:43.

  5. #4
    Pit Crew Decade Plus User onecamohv's Avatar

    My 1st Project
    Join Date
    Jun 2012
    Location
    ireland
    Age
    38
    Posts
    1,155
    Thanks
    37
    Thanked 88 Times in 78 Posts

    Re: Oil pressure advice

    hmmm still pretty inconclusive without bearing clearances, but 55psi if its at idle speed is not so bad. generally you'd see 70-80 with 20/50 cold with something like 2.5thou clearance, but having said that, im not extremely experienced on lots of pintos, so im sure someone more used to them will chime in. that might be normal with a stock pinto pump.

    you'd be really surprised with oil temp, id be surprised if you'd hit 60 degrees oil temp after running the engine without load for 15/20min.

    what pressure did it hit at 3k?

  6. #5
    Bodger

    Join Date
    Jul 2017
    Location
    Povegliano veronese
    Age
    27
    Posts
    133
    Thanks
    70
    Thanked 17 Times in 12 Posts

    Re: Oil pressure advice

    At 3k it was back a Little under 4bar, so 55/60psi.

  7. #6
    World Champion Decade Plus User alladdin's Avatar

    My 1st Project
    My 2nd Project
    Join Date
    May 2005
    Location
    s.wales
    Age
    60
    Posts
    9,200
    Thanks
    167
    Thanked 446 Times in 432 Posts

    Re: Oil pressure advice

    maybe relief valve letting go at 55 psi ? i dont know what they usually go to but im sure google can tell you. i remember a thread on here about putting a washer behind the spring.

  8. #7
    Bodger

    Join Date
    Jul 2017
    Location
    Povegliano veronese
    Age
    27
    Posts
    133
    Thanks
    70
    Thanked 17 Times in 12 Posts

    Re: Oil pressure advice

    Quote Originally Posted by alladdin View Post
    maybe relief valve letting go at 55 psi ? i dont know what they usually go to but im sure google can tell you. i remember a thread on here about putting a washer behind the spring.
    Yes I've read that thread, it makes perfectly sense the washer mod and I would have a spare one to try, but I'm pretty sure I won't be able to weld it properly, I just don't want to risk an engine over a 60£ oil pump.

    Regarding pressure, I didn't found a single answer, there someone going to 80psi hot to other at 40psi cold, I'll check it real hot on track and see what to do. I was keen to try and change the internals, but if it's the relief valve working it wouldn't change anything, so high pressure (too high?) would be the only choice.

+ Reply to Thread

Bookmarks

Posting Permissions

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