Need advice: timing belt drive bearings - DOH ! | FerrariChat

Need advice: timing belt drive bearings - DOH !

Discussion in '308/328' started by [email protected], Jul 19, 2009.

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  1. andy2175m4@yahoo.com

    [email protected] Formula Junior

    Dec 7, 2008
    473
    Los Angeles, CA
    Full Name:
    Andy Rein
    After much work, I finally got the timing cover off, and removed the timing belt drive ball bearings and gears.

    I found the rear bank timing belt drive was wobbling badly (the outer ball bearing was shredded) the inner ball bearing appeared to be wobbling a bit as well. I pulled out the shaft, and found the small inner ball bearing appeared to be fine, but perhaps the outer race of the inner ball was wobbling in its engine block journal.

    I bought all new bearings at NAPA and found the new inner ball bearing did exactly the same thing, which means the existing inner ball bearings were fine, and all the misery of removing the timing cover to replace them was a completely unnecessary waste of time and $. DOH !!! (nod to Homer Simpson)
    (well that is if the small wobble of the inner bearing is truly not a problem).

    So my question is this: If the inner ball bearing journal in the engine block is opened up a bid due to rattling of the timing drive gear, is there anything I can do about this, or just leave it as is, and wait for the next bearing changeout (hopefully after several years.

    Also, later today I will put the dial indicator on the shaft and measure the end shaft wobble, this is without the outer bearing, just the timing belt drive shaft cantilevered off the inner ball bearing.

    The thought of a liquid shim, or peening the journal somehow, comes to mind.

    Also, does anyone have quantitative information about the survival lifespan of ball bearings under finite loadings with imposed lateral displacements (aka wobble) ?
     
  2. mustardfj40

    mustardfj40 Formula 3

    Jun 17, 2004
    1,142
    Northen California
    Full Name:
    Ken
  3. duck.co.za

    duck.co.za Formula 3

    Jan 9, 2007
    1,007
    Cape Town South Afri
    Full Name:
    Dave
    Please excuse me if I'm wrong ,but if I remember correctly those are tight tollerance bearings !! Have you replaced with such ?? I know I struggled to source the correct bearing .
     

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