Lightened Flywheel?
 

What is the recommended weight for a lightened Model A flywheel? :confused:

What is the weight of a stock A flywheel? :confused:

Re: Lightened Flywheel?
 

Stock flywheel is 63
I've got mine down to 37
What's a perfect weight? I guess that would depend on engine and what would work best for your application


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Re: Lightened Flywheel?
 

I run a stock b flywheel with a stock a crank...b fly is 53lbs

Re: Lightened Flywheel?
 

I have a v8 clutch and the flywheel is about 35 lbs.

I am not saying that is the best, it is just what I have.

Re: Lightened Flywheel?
 

Here ( https://www.fordbarn.com/forum/showthread.php?t=89197 ) is a thread I started several years ago that should be an interesting read for you.


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Re: Lightened Flywheel?
 

Weight is not the entire picture. It depends on where the weight is removed. It is preferentially removed from the biggest radius. That will lower the inertia more than what the weight would suggest. The inertia is the integral of differential mass times radius squared. So the lightened flywheels can be as much as 1/4 the inertia of the stock flywheel. (A guess).

Using a lightened flywheel is a matter of personal preference. How fast do you want to accelerate from a stop light? A lightened flywheel wont make any difference in how fast you can pull a hill. It will add more torsional vibration that will feed into the transmission and that I believe I can sense.

Re: Lightened Flywheel?
 

I reduced the rotating group weight by 10 lbs with the B flywheel,added about 4 with the harmonic balancer. A flywheel stores kinetic energy and by virtue of its mass dampens impulse.
In my opinion it has to do with your vision of the car.I want the mass to aide driveability,smoother operation. Although I basically double the power output of the engine through modification I don't race.My goal is a long distance touring car with reliability,I dont need a jack rabbit off the line,but want the smooth pulling power.In traffic the kinetic energy stored yields smoother clutch operation and smooth acceleration.

Re: Lightened Flywheel?
 

Whats important is building the engine for what you plan to do with it. I know folks who invest thousands to build an engine capable of racing and drive it like a touring car.

Another thing to consider is vendors run a business and sell items for profit. Its not fully in their interest to be sure a modification they sell fits your needs. Social media forums is an area where you need to filter based on your goals for the car. Often trends become established based not on need,but on a group justifying the money they spent.

Re: Lightened Flywheel?
 

I do know that lightening the flywheel will change the torsional response of the drive line. The natural frequency will increase. But where the weight is removed is also important. I would want a technical reason, experience or expected positive changes that will result from lightening the flywheel alone. It would seem that counterweighting the crankshaft would be better in terms of vibration that occurs at about 42 mph. But again, before I would make this change, I would want to know what it gets me....vibration free engine, improved bearing life...what?

Re: Lightened Flywheel?
 

With no flywheel, when you put pedal to the metal (or wood) the energy goes to the back wheels to make you go.

With a flywheel some, or a lot, depending on weight, gets stored for later.
This saved energy transfers to the wheels when you try to slow down or are slowed down, whether you like it or not.

Re: Lightened Flywheel?
 

I'm not sure that all will be able to relate to this answer, but where the weight is in relation to the outer diameter of the flywheel, actually does affect the speed and performance.
Look at a figure skater and watch as they begin to make a spin in their vertical axis; their arms are stretched out, and as they bring their arms in closer to the center

line / axis of their body, their speed dramatically increases to a point of disbelief !
The weight never changed, just its location in the rotation. Without destroying the

structure and strength of the flywheel, removing the weight from the outer diameter

from both sides, should help in the acceleration of the motor. I'm sure your rear main bearing will thank you for the gesture too.

Re: Lightened Flywheel?
 

OK, What is the weight of a standard flywheel with pressure plate and ring gear attached?. Mine comes in at about 70 pounds.

Re: Lightened Flywheel?
 

I'm no expert, but Les Andrews says "The stock flywheel weighs 63 lbs. 4 oz. Do not drop it. Keep feet clear when lifting the flywheel into place. Feet do not mesh well with the flywheel ring gear." I can verify that this is true. Don't ask me how I know.
Marty

Re: Lightened Flywheel?
 

Many thanks to all who responded!

Re: Lightened Flywheel?
 

I weighed my just removed B flywheej, with ringgear and bearing.
It weighed 53/54 lbs.

Re: Lightened Flywheel?
 

That's just what I lightened my flywheels to! And Henry did it all by himself, Wow! I wonder why? Let's face it, Heavy flywheels steal HP! They steal it by inertia. Which is easier to turn, a bycycle wheel or a truck tire. In the 1800s, it was an article of faith that every machine have a heavy flywheel. If you need confirmation, go to any museum of old engines and see for yourself. Flywheels were huge! As engineering progressed, they got smaller and lighter. We have that change from the As to the Bs of approximately 10 lbs. Clearly, Ford engineers were aware of it in 1932.
Terry

Re: Lightened Flywheel?
 

I have heard that one of the rationales for removing the perimeter of the back of the flywheel (thereby lightening it) was to allow the three-finger V8 clutch to fit. Is there truth in that, or will the V8 clutch fit within the depression in the stock flywheel? If not, how much do you need to increase the diameter of the depression to make it fit?

The thread that Brent mentions in #5 is a very interesting read. Lots of opinions, most well-supported.

I'm coming up on building a touring engine with 6.0 head, and I'm leaning more towards lightening only as much as I need to for a V8 clutch to fit. I'm not so interested in speed of spin-up as I am in a smooth low speed idle and maintaining inertia while climbing.

JayJay

Re: Lightened Flywheel?
 

This like discussing oil. It never seems to end.

Re: Lightened Flywheel?
 

With my lack of knowledge of engines my question is what is accomplished by lightening the flywheel? Is it done in a machine shop ? Thanks in advance !

Re: Lightened Flywheel?
 

yes it is a machine shop that will do the flywheel.

With a lightened flywheel the car spools up much faster because it isn't trying to move an additional 35 lbs. Take offs at a light are much quicker.

On my car I have the lightened flywheel along with a V8 clutch. The v8 clutch makes it way easier to depress the clutch.