Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Oil Pressure - how much is too much?

  1. #1
    OK guys and gals, how much oil pressure is too much?
    I rebuilt my twin turbo motor and originally it had about 60-70 pounds at WOT. After the rebuild with a new block I now have about 100 PSI at WOT and about 80 PSI at lower RPM's using standard 10/40 oil.
    After the break-in I went to synthetic (Mobile 1 10/30) it dropped about 5 pounds at WOT and about 15 pounds a lower RPM's.
    I've heard stories of bearing wash out because of to much oil pressure. Any of it true?
    I know drag motor guys have told me that it's OK. But they run a motor for about 10 seconds. I run all day long. Any thoughts?
    [ November 06, 2002, 11:28 AM: Message edited by: 78DiMarco ]

  2. #2
    One of the biggest factors that eefect pressure is the oil temperature. I always ran in the 70-80 psi range. Then I put an oil thermostat that keeps the oil around 215 degrees. Oil pressure is 40 at idle and still goes up to about 70 at WFO. Rule of thumb is 11 psi per 1000 rpm.

  3. #3
    78DiMarco Do you happen to know what the rod & main bearing clearances were set at? the tighter the clearance the higher the oil pressure will be. Also what type of oil pump was installed when the rebuild was done? Do you have a high "pressure" pump rather than a high volume?? Were gonna need a little more info to help you wink

  4. #4
    I have run motors with 100 psi several times. I have been told that it takes 125 to 150 to wash the bearings.
    Your motor sounds just fine.
    10 psi per 1000 rpm is the lowest acceptable
    12-15 is just right

  5. #5
    K3, the rods are at .002 and the mains are at .0025, the oil pump is a high volume. My oil temp runs anywhere from 190 to 210 depending on how hot the air is and how long I have my foot in it .
    I'm going to put an additional guage on it to validate what the guage on the dash is reading.

  6. #6
    It sounds to me like you have a high pressure pump not a high volume one. You are wasting Hp and causing excess wear to your distributor drive gear. Change the pump or the bypass valve in the pump that you have now.

  7. #7
    Tink, no it's a high VOLUME pump NOT a high pressure. wink

  8. #8
    78D, I think you have a bad pump. The spring is to
    stiff or the bleed off valve is not working good.
    Moroso makes a blue printed pump works great.

  9. #9
    You are not doing your engine any good with that pump. You will tear up your distributor drive gear. 10 psi per 1000 rpm is all that you need for a performance boat engine. NO MORE NO LESS

  10. #10
    An oil pump only puts out volume. Oil pressure is created by your clearances in your engine. Oil pressure is affected by the viscosity of the oil and the temp of the oil. When an oil pump is turning at high rpm it draws about 5hp off your engine. So make sure your engines warm before you lay the wood to it.

Page 1 of 2 12 LastLast

Similar Threads

  1. 455 Oil Pressure
    By 1hd-rider in forum Jet Boats
    Replies: 19
    Last Post: 07-21-2004, 02:51 PM
  2. low oil pressure
    By 272 baja 502 in forum Gear Heads
    Replies: 13
    Last Post: 06-25-2004, 08:27 AM
  3. Oil Pressure
    By Cole Sanger in forum Sandbar
    Replies: 5
    Last Post: 12-27-2003, 11:52 AM
  4. Oil pressure
    By Just Tool'n in forum Gear Heads
    Replies: 18
    Last Post: 08-11-2003, 08:46 PM
  5. No Oil Pressure
    By 1000mhz in forum Jet Boats
    Replies: 13
    Last Post: 05-26-2002, 10:16 AM

Posting Permissions

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