Sudden Drop In Oil Pressure
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Sudden Drop In Oil Pressure

  1. #1
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    Default Sudden Drop In Oil Pressure

    Boat was bought last year, Tom from JBP's low budget build that was a work in progress in here. I only ran it twice last year for a few minutes each time, and it had an oil leak at the base of the dist. both times. I have a 454 BBC that had the stock HEI dist. that I switched out to an MSD Streetfire. First time out this year, new dist. leaked as well so I double gasket it and it still leaks, 3 gaskets later and the leak stops BUT...here's where it gets crazy...from day one, including in the video sent before I bought it, it had 80 lbs. on a cold start and ran 60 lbs. with some rpm's warm...since the three gaskets I dropped to 20 lbs. and it struggles to hit 35-40 now, I haven't pushed it at all...I determined the intake hole for the dist. was out of "level" the dist. hit on one side, not the other so I cut the one side of the intake down and went back to one gasket with no leak now BUT the low pressure issue. I checked the gauge which is new, fine, swapped out the sender which is new, fine, I changed the filter which had 10 minutes on it, no change...
    Any ideas are welcome, thanks guys...

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    Senior Member sammyc57's Avatar
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    I had an oil pump bolt that had been forgotten to torque once , did the same thing after about 15 min.

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    Senior Member Bubbletop409's Avatar
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    Three gaskets may have raised the distributor high enough to cause the oil pump drive shaft to not have enough engagement with the bottom of the distributor? Never mind, just read the whole post about back to one gasket.
    Last edited by Bubbletop409; 07-31-2013 at 09:14 AM.
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    i would hook up a mechanical guage if your not all ready using one i have had the electric ones fail/miss read just to comfirm the problem now what oil pan is on it an i dont know this could have happend but if it pushed/bent up to the oil pick up it cuase it not be able to suck

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    Hooking a mechanical up now...engine ran fine, plenty of PSI UNTIL I changed dist....

    Well as I suspected, the mechanical is the same...very low, sluggish PSI...Looks like it's internal..."IF" the spring were to break/ crack in the pump, would it still have pressure but reduced, or no pressure?...

    Thanks guys...
    Last edited by Rowdy 1; 07-31-2013 at 11:50 AM. Reason: Add text

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    a buddy of mine broke a oil pump spring in his ls7 an it would lose all pressure then get it back it was ether all or none when it happend on the that but i sure its differnt oiling between the 2 motors

  9. #7
    gn7
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    When you had 3 gaskets in it, you may have raised the distributor enough to expose the cross over groove in the distributor causing a major internal leak.
    When you say you machined the manifold, you mean you machined in intake face to get the manifold to lean to one side to get the distributor pad to even out with the distributor seating ridge? How much was removed from the manifold? What manifold is this.



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  10. #8
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    Default What I Thought Too...

    Quote Originally Posted by gn7 View Post
    When you had 3 gaskets in it, you may have raised the distributor enough to expose the cross over groove in the distributor causing a major internal leak.
    When you say you machined the manifold, you mean you machined in intake face to get the manifold to lean to one side to get the distributor pad to even out with the distributor seating ridge? How much was removed from the manifold? What manifold is this.
    I used a right angle die grinder with the medium grit pad on the open area of the intake where you drop the dist...the old HEI & the new MSD were hitting the driver side of the manifold at the base where it sits on the gasket...would hold a piece of paper there but .010 the other seating area...I would never attempt the head to gasket surface...it's an old Edelbrock Torker 2-0...I went very slow and test fit a number of times so I didn't take too much off...

  11. #9
    Senior Member riverslide's Avatar
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    Hello.
    Say did you check the distributer shaft end play, to oil pump after you machined the manifold ? If not you might have just killed the oil pump.....

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    Default No Sir

    Quote Originally Posted by riverslide View Post
    Hello.
    Say did you check the distributer shaft end play, to oil pump after you machined the manifold ? If not you might have just killed the oil pump.....
    Hello, No I didn't check that, the initial problem was or appeared to be both dist. would bottom out where the base meets the gasket under it and on top of the intake on one side leaving a gap 3/4 of the way around. Not tremendous but on my stuff, a leak needs to be fixed, especially an oil leak. How would I have lunched the pump? I can understand having the end of the dist. or the pin putting down pressure could cause wear but help me out here please...

    Thanks

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    Senior Member riverslide's Avatar
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    Quote Originally Posted by Rowdy 1 View Post
    Hello, No I didn't check that, the initial problem was or appeared to be both dist. would bottom out where the base meets the gasket under it and on top of the intake on one side leaving a gap 3/4 of the way around. Not tremendous but on my stuff, a leak needs to be fixed, especially an oil leak. How would I have lunched the pump? I can understand having the end of the dist. or the pin putting down pressure could cause wear but help me out here please...

    Thanks
    When you lock down the distributer, it should not have any preload directly on top of the oil pump shaft and drive gear. Now if their is no freepaly between them, the gear will start to eat thru the pump body.

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    Default OK

    Quote Originally Posted by riverslide View Post
    When you lock down the distributer, it should not have any preload directly on top of the oil pump shaft and drive gear. Now if their is no freepaly between them, the gear will start to eat thru the pump body.
    Understood, but my initial problem was with not being seated which would make it too high, not bottoming out putting pressure on the shaft eliminating the free play...going to try a couple more things...thanks guys...I'm starting to think pump spring or cam bearing turning...

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    Default Thanks...

    Thanks to those that took the time to reply...a broken spring was the culprit......

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    Default ReallY?

    Quote Originally Posted by Rowdy 1 View Post
    Thanks to those that took the time to reply...a broken spring was the culprit......
    Wow.. I've never seen a broken relief spring in a BBC oil pump.... Live and learn I guess..

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