BAE rear Main problem.

Discussion in 'PSI Superchargers Tech Questions' started by PROTURTLE, Apr 4, 2016.

  1. PROTURTLE

    PROTURTLE New Member

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    Has anyone had rear main issues with a clutch? is there a trick or clearance difference or what have you guys found that helps out ? I know Top alcohol cars must have it figured out. Can I get some help or Ideas ?
    Leaving at 7000 with a 3 disc Crower titanium flywheel. BAE 8 BAE block
    Thanks
     
    #1
    PROTURTLE, Apr 4, 2016
  2. jay70cuda

    jay70cuda Well-Known Member

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    Whats your main clearance. I've seen some guys plumb a -4 to the rear main right off the pump to feed the main. Or I've seen some builders add a .0005-.001 and open rear main for more oil. But the main comes down ever 4-5 passes for inspection. Maybe ti rub blocks on the clutch to help with flex issues
     
    #2
    jay70cuda, Apr 4, 2016
  3. tafc1445

    tafc1445 Member

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    Some people say an out of balance clutch will kill rear mains.
     
    #3
    tafc1445, Apr 4, 2016
  4. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    In my experience of chasing all the trick this and that's, it's usually the flywheel. The titanium scalloped ones can warp over time. Really any of them can.

    If it isn't the flywheel it can be the stands are bent/twisted.

    The next thing to check is to make sure the back of the block is square. We had a block that would kill the rear main no matter what we did until someone told us to check the back of the block. Basically have to bolt the motor plate and bellhousing to the block, remove the candlestick assembly and indicate off the crankshaft to make sure everything is square with no run-out.
     
    #4
    Will Hanna, Apr 5, 2016
  5. aj481x

    aj481x Member

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    Do you push the clutch in at the stripe?
     
    #5
    aj481x, Apr 5, 2016
  6. NITROBANDIT1

    NITROBANDIT1 LOST IN SPACE

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    I have heard brad is putting 2 mains in some blocks. it might be a old racers tale, I haven't seen one or pics of one, might be something to call on at bae
     
    #6
    NITROBANDIT1, Apr 5, 2016
  7. turbo69camaro

    turbo69camaro Member

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    Also check the clearance on the crank flange to flywheel bore i know one team that heated the flywheel to get it to go on when motor was cold and fixed there issue
     
    #7
    turbo69camaro, Apr 6, 2016
  8. JustinatAce

    JustinatAce Member

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    If your block and clearance all check out, that only leaves the clutch. Check for runout on the flywheel, if it is the culprit you'll see more runout towards one or two stands. If it is consistent all the way around, then the flywheel is good. Do the same with the hat and donut. I have seen the odd instance where the hat is warped or the lugs on the donut have been hammered out pretty good causing imbalance. Check your stands and studs too. Weigh them, and ff the stands are hammered out, they will let the floaters and donut wobble a bit too much.

    Most commonly it comes from the floaters. Floaters are purposely manufactured with a decent amount of clearance around the stands so they don't grow into the stands when hot. Otherwise the clutch won't fully release. Many have resorted to building a floater jig and drilling holes in the same exact location on each floater, then setting the holes 180 degrees apart when assembling the clutch. This kind of pre-stretches the assembly as it rotates and keeps it a little more square as you run. In the same token, make sure the lugs of the floater haven't been hammered out either.
     
    #8
    JustinatAce, Apr 6, 2016
  9. h2b puller

    h2b puller Member

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    The older style BAE blocks have more material around the nr.5 mainweb, i think they took too much material away to lighten it.
     
    #9
    h2b puller, Apr 9, 2016
  10. PROTURTLE

    PROTURTLE New Member

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    OK thanks putting all new disc and floaters in.. found the bell housing to be .080 out checking the hole with the candle stick out,,. bolted up a new one and checked the same way it was out .005 hoping that was the trouble.
    do you agree that it being .080 out could be the problem?
     
    #10
    PROTURTLE, Apr 17, 2016
  11. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    definitely a big problem
     
    #11
    Will Hanna, Apr 18, 2016
  12. Bob Meyer

    Bob Meyer Comp Eliminator

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    Absolutely; Lenco spec is .015 max. It can be terrifying what a high buck bellhousing can look like after one season in TAFC with a 3 speed hanging off the back with violent shake !
     
    #12
    Bob Meyer, Apr 18, 2016

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