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BBC questions

Discussion in 'The Garage' started by Leadfoot, Mar 16, 2004.

  1. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    I recently purchased a 454. I know the motors are externally balanced from the factory. I have seen flywheels/flexplates and harmonic balancers offered in both internal and external balance. The motor I bought was originally in front of a 4 speed manual, and I am bolting it in front of a 4 speed auto. I removed the flywheel and behind it was a "balance plate" of some sort. If I order a flexplate for an external balance motor, do I need to reuse this counterbalance or was that just for the flywheel? Also, the harmonic balancer on the motor looks like the one I have on my internally balanced 350. I "thought" that externally balanced harmonic balancers had a step or counter weight attached to them. Can anyone help, I don't want to ruin this motor.

    Also, who offers retrofit roller camshafts for BBC's.

    Thanks.
     
  2. Burt4x4

    Burt4x4 3/4 ton status

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    I'm no expert at this but with my 454 I found out that I do need to run an externally ballanced flywheel. Fom what I understand you can tell an externally balance flywheel becuse it has physical wheights welded on the outer edge of the wheel. Duno about the extra part you talked about. The dampner should be a fullsize 8" dampner for externally balanced engines. Now with that unknow part you have and the stange dampner...maby you have one of the rare internally balanced 454s??
    When I was researching this it did seam the externally balanced was the norm.
    Hope this helps a lil bit.... /forums/images/graemlins/smile.gif
     
  3. K30CJ

    K30CJ 1/2 ton status

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    The balance plate you found behind the flywheel is there to make an "internally balanced" flywheel work on your externally balanced 454. As long as you use the right flexplate for a 454, you do not want to use that balance plate.

    Did you purchase this engine from IL by chance? Might have been the one my brother just sold to someone in Mass. If so, it has the correct harmonic balancer for a 454.
     
  4. justinf

    justinf 1/2 ton status

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    Yep, what K30CJ said is correct. He's my brother and the one who rebuilt the engine.
     
  5. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    [ QUOTE ]
    The balance plate you found behind the flywheel is there to make an "internally balanced" flywheel work on your externally balanced 454. As long as you use the right flexplate for a 454, you do not want to use that balance plate.

    Did you purchase this engine from IL by chance? Might have been the one my brother just sold to someone in Mass. If so, it has the correct harmonic balancer for a 454.

    [/ QUOTE ]


    Yes that was me.

    Thanks again to the both of you. /forums/images/graemlins/waytogo.gif

    I was worried as I have not dealt with BBC's. I had one SB 400 that was externally balanced and it had weights on the flexplate and had a notched (counterbalanced) harmonic balancer. I did not see the notch in the balancer so I was a little worried. Thanks for the info though.

    PS. Is there an easy way to differentiate an externally balanced harmonic balancer from an internal one?
     
  6. K30CJ

    K30CJ 1/2 ton status

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    I know what you mean about 400's. I like those too. The big small block. Built a 434 stroker once. Now that's one hell of a motor./forums/images/graemlins/thumb.gif

    Not sure about the BBC balancers. I bought that one (and the big oil pan, and the timing cover) from the machinist who did the valve job on your motor.
     
  7. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    I know what you mean about 400's. I like those too. The big small block. Built a 434 stroker once. Now that's one hell of a motor./forums/images/graemlins/thumb.gif



    [/ QUOTE ] It sure is...I almost stroked mine to 434 when I built it.
     
  8. K30CJ

    K30CJ 1/2 ton status

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    Dude, you missed out. It's not cheap or easy, but that extra stroke makes a big difference. Had it in a mud drag truck. Beat a lot of big blocks with it. /forums/images/graemlins/woot.gif
     
  9. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    BBC 454 balancers are counter weighted on the backside of the damper and on the hub portion and not the outer ring like the SBC 400.
     
  10. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Thanks everyone!
     

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