I don’t understand .......28 oz flywheel / 50oz factor flywheel?

Scorpion65

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Sep 4, 2004
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I have a 351W. I’m told I have to use a 28 oz flywheel since the 351 comes with a 28oz harmonic balance.
My question is can I put a 50 oz harmonic balance on the eng. And use a 50oz factor flywheel?
I don’t understand to much about this balance stuff. Could someone fill me in and tell me if swapping the harmonic balance will work? If not why? Help me understand this flywheel and harmonic balance relation to each other and the eng.
Thanks
 
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Go figure…..
The harmonic balance can only go on the crank in one position because it has to matched to the keyway, gut the flywheel can be bolted on to the crank in any position even though it is off balance?
depending on where you position the flywheel, wouldn’t you think it would off balance the crank?
 
The holes are spaced on the flywheel so that it only goes one way.

You cannot swap external balance parts back and forth between motors. If the rotating assy is balanced for 28 oz the you must have a 28 oz imbalance on the flywheel and balancer. No IFs, ANDs, or BUTs.
 
Just take your 50oz flywheel to a machine shop (one that knows what they're doing) and they can do the necessary work to make it 28oz. That's what I did and have'nt had any probs.

Later
 
I didn't realise the Flywheel ( and I have changed many of clutches ) can only go on one way also...Hummmm...
As for the machine shop...I think I'll do that. As I understand the 28qz flywheel takes a 10" clutch disk where as the 50qz can take up to a 10.5 disk.

Thanks for all the input guys! MAHALO!
 
The counterweights, I know that. The site below says that the 28oz flywheel can only take a 10" clutch disk unlike the 50oz flwheel that can take the 10.5 clutch disk....Read for yourself... get back to me if it's not true....
Link to info:


http://www.fordmuscle.com/archives/2000/09/t5swap/index.php


IT SAYS:
The 50oz. flywheels are also drilled for the larger 10.5" diaphagm clutch, which the 28oz. flywheels must use the early style 10" three-finger clutches
 
From the article you quoted:

Stock 28 oz. and 50 oz. flywheels have 157 tooth ring gears measuring 13.294" outer diameter. Some 351W engines, and after market flywheels, have a larger 164 tooth ring gear which has a 14.215" outer diameter and accepts an 11" clutch. The larger clutch may not clear the inside of the T5 bellhousing.

If you take a look at some of the websites for companies that make flywheels, you'll see that you can get just about any sized flywheel in any imbalance that's desired.

In other words: The flywheel you install MUST match the imbalance of the rotating assy. The size (outer diameter and tooth count) of the fly wheel will be determined by year and application (meaning mixing and matching of tranny A with motor B etc.)
 
Just don't have the $$$$

I Just don't have the money to go out and buy a new Flywheel.
I found a machine shop that will take my 50oz Flywheel down to a 28oz for $60.00 and resurface for another $50.00 $120.00......
It an't cheap here in Hawaii.......not to mention----> $Gas 3.79m a gal???
At that price the 65 stang will only get out on the weekends... :-(
 
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Measure the difference between the two lines. You'll see that it will only go on one way. If you've "changed many of clutches", you should have realized this already.
 

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Scorpion65 said:
I Just don't have the money to go out and buy a new Flywheel.
I found a machine shop that will take my 50oz Flywheel down to a 28oz for $60.00 and resurface for another $50.00 $120.00......
It an't cheap here in Hawaii.......not to mention----> $Gas 3.79m a gal???
At that price the 65 stang will only get out on the weekends... :-(

you checked out Simmit or Jegs yet?
 
Daggar said:
If it's a stock flywheel the the year and application will be the determining factor.

Yes, I belive the stock flywheels of earlier cars were only for a 10" clutch, those years were when they also ran the 28oz. I don't know why ford decided to switch for whatever reason, Ford does stupid crap like that.
 
No ****! LOL...

No ****... I have replaced many of clutch and never noticed that
But all the clutches were on cars that were all stock...
Now I'm mixing and matching, I'm learning something new....Thanks Daggar

Now all I have to do is to make sure ( double check ) I have the rite info off the block to make sure I get the rite flywheel

Thanks again...
 
$120 doesn't sound TOO bad. It can be tough finding cast steel flywheels with a 28 oz imbalance. That leaves you with either billet steel or aluminum. THAT of course, drives the price up.
 
351w

Daggar said:
Give us the year and size of the motor as well as the type of tranny you'll be using and we can turn you onto the flywheel that fits your application.


I beleave its a 351W 1970 I'm puting in a T5 10 spline shaft 10.4 clutch disk by Centerforce.
I beleave I will need a 157 tooth 28oz Flywheel.

S&H to Hawaii.... is going to cost...