Harmonic Balancer Differences?

[Daves69Coupe]

I was thinking about getting a new harmonic balancer for my car, and while I was looking around the net im seeing alot of different options for my 302. It seems like there alot of different weight options? How heavy is the stock one and what are the purposes of the different weights?

 

[manley]

I think it depends on what flywheel/flexplate you have. I seem to remember reading that they changed the weighting... from 28 oz. to 50 oz. or something like that. So you need to figure out what you have so they work together as a "matched" set.

Depending on the engine, they are internally or externally balanced. I'm no expert, but there are plenty here that can give you excellent information and point you in the right direction.

 

[Sluggo]

What year model is your engine?

 

[crustycurmudgeon]

I believe there may also be a difference in the bolt pattern--3 vs 4 bolts--for various 302's, and also whether it's an innie or an outie--that is, whether the balancer has a lip that goes into the pulley or vice versa.

The pulley to balancer indexing is discussed in Bob Mannel's Small Block V8 book on page 9-7

He also discusses differences based on whether the balancer is counterbalanced on the inner section vs. the outside ring.

Frank

 

[66gt350]

What year model is your engine?

I'd say for 99.99999% of the engines that will work to determine the balance. But I'm one of the 0.00001% exceptions. The engine block is from the '89 GT, but the pistons were toast and the block was good. And my original 302 the block was cracked but the rotating assembly was good. Both was 0.030 over. So, I'm running the rotating assembly out of my original 302 in the roller block. So, even though I'm running an '89 block, I'm at 28 oz balance. The only thing that I had to do was to have the crank ground at the rear man for the 1-piece seal.

I'm definately an exception to every rule!!!

 

[Sluggo]

I'm definately an exception to every rule!!!

Me too. I'm running 50oz imbalance on a 400M crank in a 351 block.

Professional Products makes a balancer that can be used with three bolt or four bolt, with or without lip and has a changeable balance weight. I linked all the parts below. The top part comes with the pilot spacer and a 50oz weight.
If you buy that and the 28oz weight you'll have everything you need no matter what. They also sell lower pulley spacers to correct your belt alignment. I did not need a spacer for my setup.

http://www.summitracing.com/parts/PFS-80007/
http://www.summitracing.com/parts/PFS-91006/
http://www.summitracing.com/parts/PFS-91007/
http://www.summitracing.com/parts/PFS-91011/

 

[buening]

You can also run an aftermarket crankshaft that is zero balanced. My opinion would be to look at the current balancer and see if there are any numbers on it (assuming OEM). Otherwise, it is dependent on the balance of the crank and flywheel/flexplate.