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Thread: valve clatter in the m30

  1. #1
    Join Date
    Jan 2007
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    Dayton Ohio
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    Default valve clatter in the m30

    Over the weekend I adjusted the valves in my sons 735i. It has an m30. Discovered that one of the banjo bolts was loose and laying on the top of the head. Looked carefully at the cams and checked all of the valve clearances. Only found two valves that were a little tight and readjusted those. Reinstalled the banjo bolts with new aluminum washers and a bolt locking retainer. Have run the car several days now and there is still too much clatter. I have an m30 in my 89 535i and there is less clatter from this engine. What do I do now?

  2. #2
    Join Date
    Jan 2009
    Location
    Ann Arbor, MI
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    97

    Default

    I've adjusted the valves on an M30 just three times now, but I did them right to spec and they're always noisier than when I started. I suspect that when they've been adjusted by a pro mechanic, they get set a little tighter to keep the noise and customer complaints down. If you think it's possible one of the banjo bolts let go, though, you might as well take it back apart....

    Previous owner of my car also mentioned that factory specs are different on the 735 than on the 535 simply because they figured 7-series owners wouldn't tolerate the noise. Dunno if that's true.

  3. #3
    Join Date
    Sep 2008
    Location
    Gold Coast, Australia
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    177

    Default

    Valve clatter is normal. Its when it goes quiet is when you should be worried.

  4. #4
    Join Date
    Dec 2003
    Location
    Canada, ON
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    Default

    Changing all the excentric can help, sometime they crack or get a flat spot.
    Sometimes the top of the valve is cracked and this also create noise...

    The M30 engine will never be a smooth quiet one. The Injector noise is pretty high also.
    '85 Euro 635csi Race Turbo, megasquirt, Group A
    '92 525i Touring 5 speed, 3.46 diff, UUC 8.5lb flywheel, soon to be turbo.
    '02 Subaru WRX Wagon with STI springs, bigger sway bars

  5. #5
    Join Date
    Jul 2006
    Location
    Minnesota
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    77

    Default There's a detailed write up over on mye28.com. Check the tech stickies - What can

    Quote Originally Posted by Kibokojoe View Post
    Over the weekend I adjusted the valves in my sons 735i. It has an m30. Discovered that one of the banjo bolts was loose and laying on the top of the head. Looked carefully at the cams and checked all of the valve clearances. Only found two valves that were a little tight and readjusted those. Reinstalled the banjo bolts with new aluminum washers and a bolt locking retainer. Have run the car several days now and there is still too much clatter. I have an m30 in my 89 535i and there is less clatter from this engine. What do I do now?
    happen is that the top of the valve stem actually get cupped due to wear. Then whe you stick your feeler gauge in, it creates a bridge across the cup and gives a false reading (larger gap). I always set mine based on the gap between the cam lobe and the rocker. I set at GO 0.010 and NOGO at 0.090. This may seem tighter than spec, but the distance from CenterLine of shaft to the valve tip is LONGER than the distance from the Centerline of shaft to the contact point between the cam lobe and the rocker contact point. Therefore, small gap on rocker side creates larger gap at valve tip side. I have done it this way for my 528e and both my 535i's.
    Good luck.
    Jeff in MN
    87 535is 245k Recent top end re-work
    88 528e 290k
    90 535i 115k
    98 740i 115k New Magnaflow Cats, No More Codes

  6. #6
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    Dec 2003
    Location
    Canada, ON
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    Default

    Quote Originally Posted by Jeff in MN View Post
    happen is that the top of the valve stem actually get cupped due to wear. Then whe you stick your feeler gauge in, it creates a bridge across the cup and gives a false reading (larger gap). I always set mine based on the gap between the cam lobe and the rocker. I set at GO 0.010 and NOGO at 0.090. This may seem tighter than spec, but the distance from CenterLine of shaft to the valve tip is LONGER than the distance from the Centerline of shaft to the contact point between the cam lobe and the rocker contact point. Therefore, small gap on rocker side creates larger gap at valve tip side. I have done it this way for my 528e and both my 535i's.
    Good luck.
    Wow, this is an amazing trick.... THANKS
    '85 Euro 635csi Race Turbo, megasquirt, Group A
    '92 525i Touring 5 speed, 3.46 diff, UUC 8.5lb flywheel, soon to be turbo.
    '02 Subaru WRX Wagon with STI springs, bigger sway bars

  7. #7
    Join Date
    Jul 2006
    Location
    Minnesota
    Posts
    77

    Default You're welcome, plus it is a lot easier to get your

    Quote Originally Posted by Bruno View Post
    Wow, this is an amazing trick.... THANKS
    gauges on top of the lobe and gently adjust the eccentric on the other end. HOWEVER please note I had brain fart in describing the gap. I meant 0.090 Goes in easy, 0.010 Goes in snug, and 0.011 is a NOGO. Sorry for the confusion.
    Jeff in MN
    87 535is 245k Recent top end re-work
    88 528e 290k
    90 535i 115k
    98 740i 115k New Magnaflow Cats, No More Codes

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