Oil pressure issues.
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Oil pressure issues.

  1. #1
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    Default Oil pressure issues.

    I have asked this question before, but I am going to try again. I have a 540 big block Chev with an oil pressure issue. This is a bit of an ongoing problem, and I have received lots of information from various folks trying to help. Believe me, all the possible remedies they have offered, I have tried, checked and double checked. Now, the problem is a loss of oil pressure above 5000 rpm. No one else seems to have this problem, yet this is the second engine that I have had that has this issue.

    I run a Moroso billet oil pump and I try to maintain 65 psi hot oil pressure, so the bypass is shimmed up. I run -12 lines to the oil filter. I run a Moroso oil pan with 8 qts capacity, although I run other oil pans, (larger and smaller, stock and non stock). I have run different oil pumps. I have checked the pickup to oil pan clearance, and varied it. I have varied the oil level up and down. The engine does not sit at a crazy angle or anything. This problem has never shown itself on a dyno, (but maybe the rpm is not held there long enough).

    I THINK the pump is pumping the sump empty at high rpm. I also am considering going to a standard, stock, non high volume oil pump in an effort to correct this problem, or at great expense, change to dry sump. As I is right now, I cannot use full power, and frankly, I don't know what the solution is. Opinions?

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    Can't re-Member 28Eliminator's Avatar
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    How far does it drop?


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    I'd agree with you, but then we would both be wrong

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    It drops from 65-80, down, down, 30, 20. It would probably go to zero if I held it there. I get out of it right away, because I cannot afford to damage the engine. At idle, the oil pressure recovers quite rapidly and goes back to normal as though nothing happened.

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    Senior Member poncho's Avatar
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    I had the exact issue last year after going stroker, 468 to 500 inch....Chris Straub felt it was mixing air into the oil, pulled a quart and it got better. The giveaway was after a hard pass, I would shutdown for 5 minutes and the pressure was back to normal.....just a thought.

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    Default oil pressure

    Quote Originally Posted by poncho View Post
    I had the exact issue last year after going stroker, 468 to 500 inch....Chris Straub felt it was mixing air into the oil, pulled a quart and it got better. The giveaway was after a hard pass, I would shutdown for 5 minutes and the pressure was back to normal.....just a thought.

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    I have tried that already, it makes no difference. The only thing that I have never tried is a standard oil pump I have always used a high volume pump. My previous engine was a 468.

  8. #6
    Can't re-Member 28Eliminator's Avatar
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    Sure sound like it's pumping it dry... yikes. Windage tray in the pan?, oil aerating??..any chance of an issue with oil returning from the top?

    Just a couple ideas..

    I run a melling HV pump with an 8 at pan and never had an issue. But mine never turns more than 5500.


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    Have you tried a different gauge ?

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    Senior Member poncho's Avatar
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    Quote Originally Posted by VD Cruiser View Post
    Have you tried a different gauge ?
    Exact reason I run 2 gauges, one electric at dash and a mechanical I can turn and see on the motor.

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    Senior Member wizbang's Avatar
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    Do you run restrictors in the back of the block ?

    Have you thought about drain back lines from the heads / valve covers ?

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    If it were mine I would add 2 quarts to see if it helped....at least it would tell you if it was running dry

    Stupid question but I assume the pick up is towards the rear of the boat?
    Last edited by LiquidDan; 09-18-2016 at 08:58 AM.
    Originally Posted by gn7 "Stick to making the worlds best engine stand."

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    Quote Originally Posted by wizbang View Post
    Do you run restrictors in the back of the block ?

    Have you thought about drain back lines from the heads / valve covers ?
    If your Not running Hyd.lifters put restrictors in, its really simple









    h

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    Default Oil cooler??

    Are you using an oil cooler?? And, what filter are you using??......

    Ray
    LOUD BOATS SAVE LIVES

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    Default Oil pressure.

    Quote Originally Posted by wizbang View Post
    Do you run restrictors in the back of the block ?

    Have you thought about drain back lines from the heads / valve covers ?
    You might be onto something there. Frankly, I forgot all about that. I am not sure anymore how the oiling system is arranged in this block. It is a Brodix block with priority main oiling. The drainback could be a problem as well. I may be able to get a drill motor which will be able to spin the oil pump at 3000rpm (that would be 6000 crankshaft speed) and see if it can empty the pan faster than it drains back. Thanks for the idea.

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    Resident Ford Nut Sleeper CP's Avatar
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    Quote Originally Posted by herrhauptman View Post

    I run a Moroso billet oil pump and I try to maintain 65 psi hot oil pressure, so the bypass is shimmed up. I run -12 lines to the oil filter. I run a Moroso oil pan with 8 qts capacity, although I run other oil pans, (larger and smaller, stock and non stock). I have run different oil pumps. I have checked the pickup to oil pan clearance, and varied it. I have varied the oil level up and down. The engine does not sit at a crazy angle or anything. This problem has never shown itself on a dyno, (but maybe the rpm is not held there long enough).
    Do you run an oil cooler ? How new are the -12 lines ?

    I think checking the oil drain backs is a good idea.

    Before you go to dry sump you could do an external oil pump system:
    Last edited by Sleeper CP; 09-18-2016 at 10:54 PM.

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