Oil pressure went to zero while driving

Discussion in 'Street/strip 400/430/455' started by TWO72"s, Aug 16, 2019.

  1. cluxford

    cluxford Well-Known Member

    Just recently had a dream molar situation with my BBC in my Camaro. Turns out the oil pump completely crapped itself. I actually pulled the motor due to a blown head gasket and known broken ring but glad I did when I did
     
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  2. Mark Demko

    Mark Demko Well-Known Member

    Are you talking about the valve in the pic that Larry posted?
    If so, that valve isn't serviceable, meaning that it doesn't come apart without removing the staked in cup plug.
    That by-pass valve is what came apart in mine and my pressure dropped to 20 psi on the highway, the cup plug was not staked in, it was a new TA pump cover.
    The oil pressure regulator IS serviceable, that's the spring, cylindrical valve, and big nut.
     
  3. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    Sounds like your ok. Stuck valve . the adjustable regulater affects crusing pri. 10 psi per 1000 rpm will be a little higher with booster plate and clearanced pump.
     
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Your lowest oil pressure reading will be during hot weather when you have been at highway speeds for 20 minutes or more, and then you come to a stop and idle in gear.
     
  5. TWO72"s

    TWO72"s Silver Level contributor

    The oil pressure regulator with the spring and adjusting nut
     
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  6. TWO72"s

    TWO72"s Silver Level contributor

    Pretty sure I already have the booster plate and pump set up , built by Mike Phillips of AMP
     
  7. TWO72"s

    TWO72"s Silver Level contributor

    Thanks Larry , lost pressure somewhere along the line will get some accurate numbers tomorrow
     
  8. TWO72"s

    TWO72"s Silver Level contributor

    Drove the car today and here are my updates. Cold start at 1500 rpm oil pressure at 60lbs. Cruising at 3000 rpm 40 lbs oil pressure and 20 t0 25 pounds at 2000 rpm once warmed up. No mechanical noises engine seems strong and fairly smooth. Oil looks nice and clean and full. Now the bad news the oil pressure continues to drop way down at idle of 1K RPM to 6 or 7 lbs and drops more in gear. Any advice is appreciated , discussed with Mike Phillips and we both agree its probably time to pull the motor and find the issue. For me I am thinking bad oil pump , bad regulator oil pump valve or bearing problems. I used to have right around 20lbs at hot idle of 1K rpm before this problem. Thanks for any help guy's !
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Absolutely, if it was mine, it would come out. It wouldn't hurt to look at the pump and clearances, but if that does no good, out it should come. Your pressures are low across the board.
     
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  10. TWO72"s

    TWO72"s Silver Level contributor

    Pretty sure that's the plan Larry , would love to go through the oil pump but have been advised its very difficult to set up with the motor in the car
     
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  11. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    Just pull the timing cover to inspect the pump
     
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  12. Mark Demko

    Mark Demko Well-Known Member

    The biggest "difficulty" of doing an oil pump in the car is the gears like to fall out.
    Try this simple check, remove distributor (note rotor position)
    Using a long flat blade screwdriver, engage pump shaft, see if it turns freely (probably will)
    Next test, using LONG needle nose pliers, grab one of the pump tangs on the pump shaft and pull up and down maintaining a firm grip on the pliers.
    If you can actually feel up and down movement, the clearance is excessive.
    Remember that the pump will have oil in it, and the oil will take up some clearance and you may NOT feel any up or down movement, same with turning the pump with the screwdriver, it MAY feel tight with oil in the pump.
    If you don't find any "looseness" in the pump, the problem lies elsewhere, reason being, if the pump "feels tight" your oil pressure would be much higher than what your seeing.
    This check is by no means scientific, but its what I have done to help diagnose/set up Buick oil pumps.
     
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  13. TWO72"s

    TWO72"s Silver Level contributor

    Thanks Mark , where exactly are the pump tangs located ?
     
  14. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The oil pump drive shaft has a slot that the distributor tab fits into. That is what Mark is referring to.

    OilPumpGears.JPG
     
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  15. TWO72"s

    TWO72"s Silver Level contributor

    Thanks for the picture Larry
     
  16. bobc455

    bobc455 Well-Known Member

    Any update?

    -Bob C.
     

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