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Thread: Oil flow rate in the rocker gear

  1. #1
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    Oil flow rate in the rocker gear

    Hi all, been chasing a long standing low oil pressure issue at idle when warm.
    Big end bearings replaced, oil pump and cover replaced.
    I've read it could be worn rocker guides.
    Here is a video of the engine running while warm. Is this oil flow amount normal (at revs). There is certainly more flowing here than the other side. And there are bubbles in it, is that normal? No bubbles anywhere else.


    [ame="https://youtu.be/paYvn8vFpt8"]Video[/ame]

    Cheers,
    J.

  2. #2
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    This used to be my car. Johann is aware of the history and it would be helpful for others commenting to know it too low oil pressure; new pump, timing case, big end bearings

  3. #3
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    Thanks Greg, good thinking on providing the backstory.
    Cheers.
    J.

  4. #4
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    Quote Originally Posted by JohannC View Post
    Hi all, been chasing a long standing low oil pressure issue at idle when warm.

    Is this oil flow amount normal (at revs). There is certainly more flowing here than the other side. And there are bubbles in it, is that normal? No bubbles anywhere else.



    Cheers,
    J.
    G`day ,

    if you look inside the rocker covers you`ll see they both have tin plates of different length inside the upper parts they are for some control of the oil splash .

    The bubbles should not be there .

    When you say no bubbles anywhere else do you mean in the rocker gear ?

    Can you still get these bubbles when the engine is cold ?

    The pedestal that your video is showing is where the oil first enters the rocker shaft , there is only one entry point for the oil ( on each bank above cylinders 1 and 2 ) then flows along to the other end .

    The Pedestal is feed from an internal drilling which passes through both head and block .
    PLR or peter r elsewhere
    BA KA MA RRC L322 TD6 R1200GS

  5. #5
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    No I didn't notice the bubbles when it was cold. And yes, this was the only place I saw bubbles like that, the other side didn't do it.
    I just wondered if the rocker action on the shaft frothed up the oil slightly, causing bubbles.
    What else would make it bubble?

    And if the low oil pressure at idle is not being caused by the bottom end, the pump, or the rockers, what is left? Camshaft?

    Theory: Is it at all possible to suck air into the oil system with a cracked pickup tube or faulty O ring resulting in lower pressure and bubbles?

    Cheers

  6. #6
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    G`day ,

    the place you`ve found the bubbles is pre- the rocker gear so the cause must be back from .

    Where you`ve found the bubbles is pretty much the end of the oil trail it only goes to the end of the shaft .

    Backwards as far as oil flow goes are the camshaft journals and lifters/tappets then big ends ETC till it reaches the pickup/strainer .

    A faulty tappet could cause the bubbles but i would expect other things would be happening at the same time such as one tappet being noisy and then another and on start up each time hot or cold , a tappet noise .

    If you are certain it only has bubbles on one side and not the other , although it is one oil system , each side set of tappets use separate galleries that the tappets sit in and the drilling through the block and each head is also individual .

    Bubbles one side only may be narrowed down to one bank/gallery of tappets .
    These galleries also have welch plugs on the end .

    If it were mine and presuming you don`t have use of a gauge or adapters .

    I would get it warm and unscrew the oil sender out of the timing cover and either remove the O ring or just leave it a bit loose so there is some oil flow and see if there are bubbles , i understand it would hard to see and do but maybe from beneath .

    I would try a similar thing with the cooler pipes .

    I would remove the sump and check the strainer and pipe and O ring/gasket , checking would also involve looking for cracks under pressure and heat in the pipe ETC .

    This being for elimination and piece of mind because this is where the flow starts and it seems that it was for quite a few kilometers working ok so something has gone wrong like a crack in the pick up that is worse when hot and from what i`m reading it is temperature related , although the only oil pressure figure i`ve seen quoted ( RRN ) seems very low in itself but it depends how and when it was taken .
    PLR or peter r elsewhere
    BA KA MA RRC L322 TD6 R1200GS

  7. #7
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    Thanks Peter, a very comprehensive list of things to try.
    Hopefully will have some time next week to have another play around and see if I can narrow it down further.

    Cheers,
    J.

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