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Thread: M50 hydraulic lifter issue

  1. #1
    Join Date
    Dec 2008
    Location
    Gent, Belgium
    Posts
    23
    My Cars
    1987 325i, 1982 528i

    M50 hydraulic lifter issue

    Hi guys

    I have a 1991 E36 325i that had noisy lifters. Replaced all of them with new lifters from INA.
    The old ones you could compress by hand, the new ones feel solid. I used vacuum to get all the air out the lifters before fitting them.

    Upon first start with the new lifters, the engine was tapping hard and was running at very high idle (1500rpm), along with some misfires. Getting it up to temperature didn't help.

    Removed the whole valve train to have a look. 30% of the bores for the lifters are ruined...
    I have plenty of parts laying around, but don't want to put everything back together and have the same issue.

    I measured the lifters, and they are within 0.03mm of the old ones. I tried compressing them, and it takes 1.5T to get them moving. Which makes sense of the check valve seals properly and there is no air inside.

    Anybody has an idea what went wrong?

    Cheers
    Tom

  2. #2
    Join Date
    Mar 2006
    Location
    NJ
    Posts
    339
    My Cars
    1998 328is, 2006 330ci ZHP
    Just rebuilt my M52 with new cams, cam carriers and INA lifters. I noticed the clearances with the lifter bores were close but acceptable. I soaked the lifters in oil for 24 hours and then pulled a vacuum on them. I used assembly lube on the lifter bores. First start was fine and the engine continues to run well (knock on wood) after 800 miles.

    Did you time the engine correctly?

    Did you wait the requisite time after installing the cams to allow the lifters to bleed down?

    I'm wondering if you've bent valves...that would certainly explain the misfires.

  3. #3
    Join Date
    Dec 2008
    Location
    Gent, Belgium
    Posts
    23
    My Cars
    1987 325i, 1982 528i
    The INA lifters were packaged in an oil bottle, so I don't think soaking them even more was necessary.
    I did the timing using a tool like this:
    792473_x800.jpg
    During disassembly I did notice that the intake cam was too much advanced for the tool to fit. So when assembling, I mounted it a little bit retarded to fit the tool.

    What do you mean with requisite time after installation? Do you mean the lifters could be too thick when fully filled, and actually opening the valve a little bit when there should be zero lift? That is probably not the case, as we installed the intake camshaft first, waited 2 weeks for the exhaust camshaft (2 wrong lifters were supplied). The engine was however started soon after the exhaust camshaft was installed, but damage is on both sides.

    When the lifters are new and cold, they seem to behave like solid lifters. We turned the motor by hand a couple of times without spark plugs in it. There was no resistance, so I can't really believe there would be piston/valve contact when the engine is running.
    I will check with an endoscope and also measure if the valve stems are all in the same position.

  4. #4
    Join Date
    Jun 2002
    Location
    Aberdeen, NC (yes, again)
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    23,673
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    E39M5, E500 4WD
    Quote Originally Posted by Soundstorm View Post

    What do you mean with requisite time after installation? Do you mean the lifters could be too thick when fully filled, and actually opening the valve a little bit when there should be zero lift? That is probably not the case, as we installed the intake camshaft first, waited 2 weeks for the exhaust camshaft (2 wrong lifters were supplied). The engine was however started soon after the exhaust camshaft was installed, but damage is on both sides.

    .
    Doug is referring to the following BMW instruction:

    "Attention must be paid to the following if work had been carried out on the cylinder head, for which the camshaft was removed:
    Hydraulic valve tappets expand when without load from the camshaft and must be allowed enough time after installation to constrict again. For this reason, fast assembly could cause "closed" valves to still be open and have contact with the pistons.

    The following waiting times are necessary between installing of the camshaft and mounting the cylinder head.
    Room temperature (20°C) 4 min.
    10°C .. 20°C 11 min.
    0°C ... 10°C 30 min .

    Working on valve timing gear with cylinder head installed:
    Turn engine approx. 30°opposite the engine direction of rotation on the central bolt. In this way none of the pistons will be in TDC.
    Install camshafts in such a way that peaks of cams for cylinder No.1 point to each other. Mount camshafts and secure with special tool 11 3 240.

    Keep to the above mentioned waiting times. Turn engine from the 30 degrees before the TDC setting in the direction of rotation to the TDC setting and mount the timing chain."



    In other words, you must not bolt down the camshafts with the engine at top dead center.

    Now, that said, while this might possibly bend a valve, I see no way this could damage the lifter bores. On that, I have no answer, without having been there for the assembly, sorry.
    Last edited by bmwdirtracer; 11-24-2017 at 09:48 AM.

    Chris Powell
    Racer and Instructor since, well. decades, ok?
    Master Auto Tech, owner of German Motors of Aberdeen
    BMWCCA 274412
    German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471

  5. #5
    Join Date
    Dec 2008
    Location
    Gent, Belgium
    Posts
    23
    My Cars
    1987 325i, 1982 528i
    Thanks for the info. Didn't know that, so the lock pin stayed in the flywheel all the time.
    But that would mean that there is only a chance of bent valves on cylinder 6. Valves are in closed position on cylinder 1 when doing timing, and by the time the crank was being rotated, the waiting times have long passed for the other 4 cylinders.

    The damage on the bores is mostly on the opposite side of the oil feed hole of the bore. I'm thinking more in the direction of a blocked oil channel.
    The engine only has 80000km, but doesn't look well maintained. A lifter that is already making a tapping sound could've been from lack of oil. So maybe replacing all of them was never going to be the real solution.

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