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crank pulley

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by JTB, Jun 3, 2001.

  1. JTB

    JTB 1/2 ton status

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    I was installing my crank pulley when I noticed four drilled out sections on the back of it. I know this is for balance, but is it to balance the pulley itself or the pulley with the crank? I bought my blazer without a motor but the guy gave me all the accesories and I'm not sure if the pulley was balanced specifically for the motor he had in it before I bought it. It is much heavier then the other crank pulley I have. That leads me to another thought. The other pulley is larger. (in diameter) Does this have a positive or negative effect? I don't want to ruin my rebuilt motor because a pulley is not lined up correctly with the crank and is out of balance. Thanks for the help!
    Jeff
     
  2. K5krazy

    K5krazy Registered Member

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    Pulleys are balanced to themselves. I just rebuilt my motor and the balancer, pulleys and the torque plate were balanced to themselves. Only the rotating assembly was balanced together.
     
  3. Triaged

    Triaged 1/2 ton status

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    The pullies are ballanced to themselves unless it is a 400 that has an externally ballanced crank.

    '71 Blazer CST with alot of rust
     
  4. JTB

    JTB 1/2 ton status

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    How would I be able to tell if it was an externally balanced 400 pulley? I don't know what was in it before I bought it.
    Jeff
     
  5. BobK

    BobK 1/2 ton status

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    I think the 400 are 8" across were the internally balanced 350 is only 6" across.But don't quote me.

    <font color=green>BobK<font color=green>
    <A target="_blank" HREF=http://www.zing.com/picture/p8947726813026de684f60e0bd6f3fbfe/fe8f5839.jpg>http://www.zing.com/picture/p8947726813026de684f60e0bd6f3fbfe/fe8f5839.jpg</A>
     
  6. Steve_Chin

    Steve_Chin 1/2 ton status

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    Are we talking about the pulleys or the harmonic damper? The damper is drilled for balance. My original 350 damper was 8" OD. My FluiDampr is about 7-1/4" OD. I believe the way to tell a 400 damper from a 350 damper is to look for a large raised balance pad on the ID of the damper hub (I don't have a 400 damper, but that's what I've seen on other makes that were externally balanced).
     
  7. fatdog

    fatdog Registered Member

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    All of the dampers on my 400's are factory GM and they have what looks like a notch or grooved area cut out around part of the outside edge of the damper. Not sure about aftermarket 400 dampers, I've never run one.

    '65 Turbo Corsa
    '69 Elcamino
    '71 Chev 4x4 Short Step
    '71 GMC 4x4 Long Fleet
    '72 Chev 4x4 K5
     

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