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Oil Pressure Questions

Discussion in 'The Hokey Ass Message Board' started by Lukcarnut, Apr 30, 2013.

  1. Lukcarnut
    Joined: Apr 6, 2013
    Posts: 41

    from California

    Hello, I have a 440 dodge, I installed a milodon oil pump with a external pickup the pan is a milodon drag pan (holds aprox 11 qrts) with a swinging pickup and 2 feed hoses to the pump. When the engine is cold the oil pressure is above 100 psi, cant tell how far above since the gauge i have only reads to 100. When it warms up the pressure reads about 80psi at idle. i am running 15 /40 wt oil.
    Is this too much Pressure? Even with 11 qrts of oil do i run a risk of starving the engine of oil? Should i run thinner oil? Do i run a risk of blowing out seals, gaskets or even a head gasket, because the oil runs through the head for lubricatoin to the rockers. I dont think there is a way to adjust this pumps pressure but I dont know. Any thoughts?
    Last edited: Apr 30, 2013
  2. Lukcarnut
    Joined: Apr 6, 2013
    Posts: 41

    from California

    Joined: Nov 9, 2008
    Posts: 270

    from Ohio

    is the guage reading correct, check it
  4. blackcreek
    Joined: Apr 3, 2013
    Posts: 22


    I would say the pressure is too high. Not good will let the oil fiter bypass when oil is cold. High oil pressure also robs hp. I would use a shorter spring in the o/pump and drop the pressure to about 75 psi cold and about 35 to 40 psi when hot. The pressure could even be lower at warm temps as the miliodon pump you have is a hi-volume unit and if you stuff is in good shape you got lotsa oil.

  5. pinkynoegg
    Joined: Dec 11, 2011
    Posts: 1,136


    what gauge, mechanical or electric?
  6. Diavolo
    Joined: Apr 1, 2009
    Posts: 819


    Assuming the gauge is correct... YES!

    I don't know what clearances you have but you shouldn't be pegged out like that. Too much pressure causes lots of bad things, including, hp loss, blowing oil past the bypass (if it's even working at this point), pump wear, blown seals... there is even plenty of people stating (I don't know how true) that too much pressure will wash out your bearings.

    Bob is the oil guy and others recommend ~10psi per 1000 rpm. Warmed up at idle would mean 5 psi would be fine and 20-40 psi at normal operating conditions. If a motor is new, I could see adding 20 psi to those numbers but an old engine, like my old 300 that had 300K miles on it, had no issues running and I am pretty sure it idled with about 5 psi with all the loose bearing clearances.

    You didn't say the engine is freshly built so I assume it is. I would be running no more than a 10W 30 wt. oil and probably thinner depending on the build clearances.

    google "too much oil pressure bob is the oil guy" and see for yourself.
  7. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,331

    Dan Timberlake

    Permits adjustment of oil pressure externally even when the engine is running, a very valuable asset for dialing-in desired oil pressure. Ideal for compensating for low oil pressure on street application or excessively high oil pressure on the track (more than 75 PSI hot is usually unnecessary and uses wasted horsepower to drive)."
  8. Lukcarnut
    Joined: Apr 6, 2013
    Posts: 41

    from California

    Its a new mechanical gauge.
    Ill look into the spring and maybe call milodon too.
    The engine has about 50k miles on it i was told.
    Thank you all for your input
  9. George
    Joined: Jan 1, 2005
    Posts: 7,460


    Keep in mind the new CJ diesel oil doesn't have the zinc levels that the old CI oil had.
  10. mustangmike6996
    Joined: Apr 7, 2013
    Posts: 147

    from the D

    I would try 10w30 and see if it changes once you get a response back from them.
  11. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,331


    With the relief valve stuck oil weight won't help. What happens above an idle?
  12. nxcess
    Joined: Mar 30, 2013
    Posts: 109

    from Mesa, AZ

    If you can adjust the pressure relief valve, that is the best way. Do not go to a shorter spring, go to a softer spring, ie; more coils at the same length or thinner wire dia.
  13. Andrew Williams
    Joined: Feb 20, 2007
    Posts: 223

    Andrew Williams

    i agree with diavolo. i have one that runs around 5-8 hot idle and around 20-30 running hot it has about 200K and it had been like it for years. also a truck with a 318 that is about the same. a rebuilt one should be higher but not that high.
  14. bobby_Socks
    Joined: Apr 12, 2006
    Posts: 938

    from ǑǃƕǑ

    440 Chrysler I would say you need to change the spring in the oil pump. You have a high pressure spring/pump and need a hi volume with the 11qt. pan.
  15. mustang6147
    Joined: Feb 26, 2010
    Posts: 1,847

    from Kent, Ohio

    You guage reads pressure even if its volume. I say your fine. I ran those numbers on a 351 w for many years with no issue.... It may be the oil your usin? I never take the first number over 10 unless I am using straight weight.... Like 30 HD by Castrol.... otherwise 10 w 50.... You could try 20/50, but you may have the same issue.... I say your fine.
  16. YES it is too much pressure! WAY TOO MUCH! High oil pressure not only kicks the by pass valve open, it also creates excessive friction and heat. You also can push seals right out of the motor. You can actually spin a bearing from too much pressure causing hydraulic lock. Had it happen on a 4 cylinder race motor on the Dyno at Louie Unser's back in the 80's.

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