internally balanced and externally balanced.

[1966satellite]

Are there any differences in torque converters and flex plates on internally balanced and externally balance engines? If so how can you tell which is which?

 

[MikeyT]

Yes, a big difference on flex plates... You need to find a flex plate that counter balances the externally balanced engine. However, to the b est of my knowledge torque converters are the same for both internal and external balanced engines. Getting an externally balanced fle plate isn't too difficult most of the companies such as TCI, or B/M have them.

I hope this helps

mikey

 

[1966satellite]

Thanks Mikey! I have several flex plates. How can I tell which is which? Also I'm boring an externally balanced 440 .030. Since the new pistons will be larger and therefore probably heavier, do I need to rebalance?

 

[bm02tj]

Yes and the weights for external balance are on the torque converter but after market or by your engine balancer they can weight the flex plate

 

[MikeyT]

It is hard to tell by looking at them, but check the art number on it and cross reference the company. If you are unsure, you can contact summit racing and order one, they are about $70 dollars or so.

You know that question about the bore is a good one.. I would say yes on that based on the heavier nature of the pistons, but don't quote me on that..Machine shops will do it fairly inexpensively.

Mike

 

[Meep-Meep]

Externally balanced engines have an offset weight on the converter and damper.

If you are using stock replacement pistons balancing should not be necessary. KB and other aftermarket replacement pistons will require rebalancing.

 

[1966satellite]

Does that mean if I use a torque converter on my externally balanced engine that was originally on an internally balanced engine it will be neutral balanced and I will need to take it and my flex plate to the engine guy to balance everything?

 

[bm02tj]

On my 400 the shop added to flexplate when it was ballanced and I used a Zero balance converter

 

[Meep-Meep]

Externally balanced means the crank counterweights are not heavy enough so mass must be added on the outside of the engine to put the assembly in balance. That external mass can be added to the converter OR the flex plate but not both (unless the mass is split, but no one will do that). Radius also plays an important roll and the closer to the axis of rotation you get the more mass is required to maintain balance. I only brought this up so you don't get tempted to remove the weight from the converter and put it on a flex plate at a much smaller radius.

 

[1966satellite]

internal/external balance

Externally balanced means the crank counterweights are not heavy enough so mass must be added on the outside of the engine to put the assembly in balance. That external mass can be added to the converter OR the flex plate but not both (unless the mass is split, but no one will do that). Radius also plays an important roll and the closer to the axis of rotation you get the more mass is required to maintain balance. I only brought this up so you don't get tempted to remove the weight from the converter and put it on a flex plate at a much smaller radius.

Thanks for the explanation. I'll take a close look at my converters to make sure I use a neutral balanced one when replacing my transmission.