OldCarBum

As most of you are aware I'm stroking my 73 454 to 496 cu. in.
The only thing I'm not replacing on the motor is the original block.
I'll be running an internally balanced forged crank, forged rods, forged pistons with a final cr of 10.3 to 1, hydraulic roller cam, aluminum heads and other goodies.
I'm looking at harmonic balancers and noticed they are made from aluminum, steel and iron.
I don't see anything different in the specs that show which one would work best for my motor that will be used for the street and some spirited driving.
The cost differences are substantial and seem to start at around $80.00 and run up over $500.00.
Is aluminum better because it's lighter and will add less mass or does the weight of steel assist to the motors rotation?
Any suggestions and information would help.
Thanks, Greg

derekderek

I would think the extra weight would help it to dampen vibrations better than a really light one would. I also think expect that all rotating assembly, balancer flywheel in all is going to be balanced?

OldCarBum

Yes the machine shop will be checking and balancing everything internally.

MelWff

Aluminum appears to be the most expensive with iron the least. Looking at what Summit Racing offers I came up with one which is steel and is in the middle of the price range.

https://www.summitracing.com/parts/n...make/chevrolet

Sigforty

Aluminum is more expensive. You should also see if it is a SFI approved balancer. The SFI rating typically means it is tested to a certain criteria. Pioneer makes a decent priced steel SFI on in part number 872025. I personally have a Power bond 1018SS for my 454 build. It is a nice piece.

Jebbysan

Given that you are running high quality parts....I recommend this unit and they are the best out there:

https://www.summitracing.com/parts/ati-917060/overview/

You simply cannot buy a better balancer for the money and it is rebuildable.

You want the smallest, lightest balancer possible that still works well.....this covers that. They make an aluminum unit too....but pricey.

Jebby

Big2Bird

Do you like those fluid dampners Jebby? I remember they were the cats azz years back.

Jebbysan

You know what? They really do work well......do you know why I do not recommend them?
Years ago we had a Top Sportsman customer with a 632......his Fluidampr was 10 years old at that point and we decided to replace it. So we were hanging out in the shop and decided to cut the old one open display style.....guess what? After 10 years of heat cycling.....the silicone inside was HARD AS A ROCK......soooooo.....no more Fluidamprs.

Jebby

Big2Bird

Makes perfect sense. Thank you. I have a buddy with one on a 55 Bird that sits a lot. If it starts rockin like an old Maytag, ill look there.

69ttop502

I believe Power Bond makes the Pioneer. I have above referenced Pioneer on my internally balanced 502. It is a nice piece. Saves a few bucks over the ATI and is SFI certified.

cardo0

Generally the heavier/larger diameter harmonic dampners do a better job at dampening the crank pulsations. Some owners race in classes that require a SFI dampner but not that it will make more power or your car go faster.
My experience is not to spend for the expensive parts until I know I need them. Paying more for something you don't currently need but consider it possible in the future is more likely going to waste good money that could be spent on something else.

Then there are some that race only their cars and don't use a dampner at all since many late models are zero balanced on the crank snout/dampner anyways.

Jebbysan

You are exactly right about a bigger balancer being able to snuff out harmonics better.....BUT.....on a pro balanced internal assembly....the smallest one available is really the choice.....Big Blocks have a LOT of rotating mass.....and this is an area that one can shave a few pounds for relatively cheap.
I also cannot stress enough about buying a unit with the timing marks on it. Most engines of the level that the OP is building use some kind of Ignition box......a dial back timing light can be off due to a mulititude of reasons but I have seen it. I timed 40k racing engines with a strobe and marks and you should too!

Jebby

OldCarBum

I am looking at the ATI.
I have to call and talk with their customer service techs and get the right part number for my build.
Everything I find on line shows for 396/402/427 internally balanced BB's and nothing listed for a 454/496/502 build.
I agree that this is an easy way to reduce some rotating mass off the crank and would like to run one of their aluminum/steel balancers.

Jebbysan

OldCarBum

I called ATI this morning and you are correct. The 917060 is the correct part.
They also have it in an aluminum shell that takes an additional 5.25 lbs off the rotating mass.
Their tech said I would never know the difference on a street car, but weight is weight, right???.
Thanks, Greg

Jebbysan

You really will not know the difference......it is more the smaller diameter than the overall weight....and the ATI is a ton lighter than a stock 8" GM unit.......you'll see when you get it.
We put the 060 on everything up to 705 cubic inches back then.....it just works.

Jebby

OldCarBum

Sounds good, and it looks like Summit has it at a descent price.
Thanks,
Greg

Jebbysan

7t9l82

You may not notice the difference, but it certainly won't hurt anything..I went to a 9.5" 2800 Stahl convertor,while the higher flash helps performance the lighter mass allows the engine to Rev quicker thus making the car accelerate quicker.there are guys that will tell you a certain cfm carb either vacum or mechanical will produce the same power.but guys that go with mechanical carbs swear they make more power,but really it's just the car responds much quicker.I have to agree a lighter balancer won't likely make much difference,but combined with other things they have a stacking effect.if it were me, I'd go with the ATI unit,why? Because Jim beatie was a genius! He was very helpful to a kid competing in a pro class against some big names years ago.he gave me the same stuff he gave to the big guys and made sure I knew I had all the tricks,and he was enough of a friend to tell me ,you need to go to a lenco, the clutch turbo and the four speeds are forever dead in pro stock. Sorry,I got off subject a bit,I find myself getting older and sentimental. I love to see the older guys helping younger guys,because we used to be young.

TCracingCA