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Depends on what your dealing with in cranks, the benefit will depend on the RPM window you want to run. The stock 50oz imbalance at the end of the crank causes a load around the middle of the crank at RPM. As you decrease the amount of imbalance suspended from the ends of the crank the amount of vibration initiated in the middle of the crank is also reduced.

At zero, the inner throws carry the neccessary weight to counter balance the rod and pistons on the crank.

Below 6000 RPM not worth it at all. A quality balance job will be fine.

Stuff getting up in the 8000+ RPM range should be internally balanced.

Cheap aftermarket forgings, as well as stock stuff will cost a small fortune in mallory to get the weight added. Higher end stuff from the aftermarket world will cost less in balancing as Mallory is $75.00 a slug, and your paying machinist time for the drilling and insertion.

My nillet steel crank actually had to have over 3lbs removed to get to zero balance with steel rods. If I had used aluminum it would have been even more. But drilling and shaveing is cheaper than mallory slugs.
 

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Kim, does going to a 28oz imbalance help anything? If I understand, you say the 50oz should be ok for 6000rpm,.. would the 28oz be recommended if reving to 7000rpm or something?
 

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Neutral balance should be done to every car IMHO if it is not crazy expensive.

In my case it would have been another $600 to get mine done, so I decided on 28OZ. The lower the better, and yes 28 is much better than 50, and neutral is much better than 28.

There is no real set RPM limit it depends on the quality of the balance and machine work.

Neutral puts less strain on every part of your engine, call a local engine builder and ask what he / she thinks. My local guy, very well known, always recommends neutral if it is only 200-300 more. If you would like I could pass on his number..

Ian
 

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Discussion Starter #6
The way I am looking at it is $300 for a good balancer. If I figure that into the 0 imbalance then that makes it that much cheaper. The only bad thing is if something does go you don't have the balancer left over.:eek:
 

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The "balance" remains the same, or whatever the engine needs. The difference with 0 Imbalance is that your not hanging the weight off the end of the crank, at the harmonic balancer and flywheel.
 

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Discussion Starter #8
kim said:
The "balance" remains the same, or whatever the engine needs. The difference with 0 Imbalance is that your not hanging the weight off the end of the crank, at the harmonic balancer and flywheel.
Does that mean you still need an expensive balancer? I thought with internal balancing all you would need was a spacer to put your pulley on.
 

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Yes you still need a nice balancer. We use PowerBond, I have bought three myself, they work great, look great, and are very cheap.

Jack @ www.musclemotors.com gets them at smoking deals.

Ian
 

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Think of it as a harmonic "dampner" versus the improper use of balancing the dampner has the cneter ring, an elastimer band and an inertia ring. The weight of the inertia ring is used to cancel harmonics in the crank... So a good quality one (SFI rated) will prevent vibrations from building in the crank that cause the caps and main webbing of the block to fail.
 

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Discussion Starter #11
kim said:
Think of it as a harmonic "dampner" versus the improper use of balancing the dampner has the cneter ring, an elastimer band and an inertia ring. The weight of the inertia ring is used to cancel harmonics in the crank... So a good quality one (SFI rated) will prevent vibrations from building in the crank that cause the caps and main webbing of the block to fail.
Okay...well that answers that question. I guess I misunderstood when I was reading about having a motor with 0 imbalance. Either that or it was bad info which could very well be true as well. Thanks for the help fellas.

With that being said I will not be going with a 0 imbalance.;)
 
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