Harmonic balancer Question

[65coronet440]

I got a little wobble on my harmonic balancer, ive had a bad vibration that ive been chasing for 4 months now, but whether this fixes it or not, it needs to be replaced...

So ive been looking at some on ebay and summit and a few other places. Ive noticed that there are different weights and O.D diatmeters, is there a way i can fiqure out what i have before i order a incorrect one.

I saw a few that were 30 dollars to 300 dollars, i dont want to get a cheap one because my engine is far from stock...

so any suggestions??

 

[Cranky]

How far from stock are you? If you need a SFI balancer then you need to spend the money. Stock balancers don't cut it on non stock engines that turn higher rpm. Stockers can come apart too easily especially if they are older.....

 

[65coronet440]

I dont have any offical HP numbers, but it runs a 12.43 in the quarter. and still has a unused 200shot, im thinking 550-600hp at the flywheel W/O spray

I saw the SFI balancers, and thought that would be the way to go....
but i had to ask around first..

If im in that deep, any suggestions for additional repairs?

 

[696pack]

What you need to know in order to get the correct balancer is weather you have an internally or externally balanced engine. The forged cranks are internally balance and from the factory had a much smaller balancer than the cast cranks.

 

[65coronet440]

Is the a way to find this out?

 

[696pack]

The factory original 440 steel forged crank balancer is 7 1/2" X 1" the cast crank on is larger.

 

[Meep-Meep]

Harmonic balancers (actually called harmonic absorbers) are pretty specific in terms of what frequency they absorb. Their purpose is to keep the crank from twisting due to shock loads from the cylinders firing at various engine speeds. TCI has one based on old aircraft technology called the "rattler" and supposed to absorb various frequencies throughout the RPM range but it's something like $300.00+ Also the cast cranks will be externally balanced so the absorber will have a weight in one particular area.

 

[splicer]

I used a Performance Products #90013 balancer on my BB stroker...

It comes with 2 weights to use on externally balance engine or, use no weights with internally balanced engines...
Same thickness as stock balancer so pulley lines up and SFI approved...

They also make a non approved balancer for less money..

I'm happy with their product...


Splicer

 

[Cranky]

Factory cast crank balancers have an offset weight cast into them and are fairly thick....the forged cranks had a thinner unit and are concentric but the outside diameter is close to the same on both. 6 pack engines (forged cranks) were externally balanced due to the huge rods they had.....