Heavy vs. Light Flywheel

[M Bray]

Which do you think is better for a Div. 5 tractor?

 

[Dirt Slinger]

I'd go steel flywheel. Saftey first and foremost! !!

 

[buickanddeere]

Heavier is better to soak up impulses

 

[H-66]

I think it depends on what RPM range you are going to turn. If you run low RPM don"t you want a heavier flywheel? Steel flywheel is the way to go but like he said do you want heavy or lite? I am interested in others experience either way.

 

[Anonymous-0]

the weight of steel and cast iron is close so that doesn't help him any, a light flywheel is for high rpm's and quick throttle response, neither of which really apply to an antique puling tractor, rotating mass doesn't hurt horse power but reciprocating mass does

 

[Dirt Slinger]

He did say div 5.

 

[VicS]

The drop pan sled guys run a heavier flywheel. My neighbor who races modified stock cars doesn't have a flywheel (8 in) The starter is on the trans.

 

[H-66]

Thanks dboll, That's the way I was looking at it.
But I am no expert by any means.

 

[gtx1967jewison]

So- you're saying a 1000# wheel takes NO MORE hp to turn than a 100# wheel???!! Heavier the wheel, the less power remains to turn the axles. Period. Maybe only a fraction of a hp but it's a fact. Take a tire off your wife's car & push it across the yard. Now a semi tire. Hmmm....

 

[toolz]

It takes more energy (horsepower) to ACCELERATE a heavy flywheel, but the same to keep it at a steady speed. A heavy flywheel will also retain more energy as the engine decelerates. Your example of rolling a tire has nothing to do with a flywheel. Rolling resistance is completely different than spinning a flywheel.

If pulling a drop sled that is going to kill your engine, a heavy flywheel will out-pull a light one. If your tractor has the power to spin out every time, flywheel weight isn"t going to matter.

 

[Anonymous-0]

Largest diameter you can fit in bell housimg .The larger in diameter it is the less it has to weigh to transfer the same amount of torque to the wheels that a smaller diameter heavier flywheel does.

 

[M.Genrich]

Well said tools! You only forgot one thing. A fifty pound flywheel is a lot more attractive than a one hundred pound flywheel when you cross the scale.

 

[Anonymous-0]

I don't claim to be one either. Fortunately toolz elaborated further. A heavy flywheel balanced to the crank takes no more power than a light one but stores up more inertia. It does take more to get it up to speed. Unless someone is pulling a Rumley Oil Pull I don't know of any tractor with a 1000# flywheel.

 

[toolz]

Good point, M. I've never had a tractor that was that close on weight, but the 150lb+ flywheel on my MM 800 would certainly make a difference if I did!

 

[H-66]

10-4 to that.

 

[BushogPapa]

Good question...

JD 2-Cylinder tractors doubled in size still use the Flywheel they were Born with and do just fine..

Less harmful Harmonics on the Crankshaft too with a lighter flywheel..

Ron.

 

[Anonymous-0]

All I can say is if your running anything over 20% on RPM, for heavens sake get a steel flywheel. I've seen first hand what happens when a cast flywheel explodes and it ain't pretty!

 

[FactoryFarmer]

(quoted from post at 20:18:15 12/30/13) So- you're saying a 1000# wheel takes NO MORE hp to turn than a 100# wheel???!! Heavier the wheel, the less power remains to turn the axles. Period. Maybe only a fraction of a hp but it's a fact. Take a tire off your wife's car & push it across the yard. Now a semi tire. Hmmm....

A heavier flywheel gives you more torque.....since going to a heavier, steel flywheel on my G the tractor lugs way better.

 

[Anonymous-0]

I went from a stock flywheel clutch n pres plate in my WC ( 85 lbs ?)that I only turn 2k with, to a 2 disc clutch setup with a thin flywheel , two discs, and stock pres plate ( 48 lbs). If I cut the motor loose, I think it would run well. I pull in the 4,5,6 mph classes and the motor is way to responsive with the light setup. It bucks too hard. I'm still working on it and I think I may have it figured out. Either way, it pulled just as well if not better with the twin disc, just wasnt smooth. That's my experience.

 

[Anonymous-0]

Andy , I told you so over on allis forum so sid dr allis when marty was showing it off I guess some have.to learn for themshelf

 

[wi50]

It's to bad that his carb issue has caused ML to show his ignorance once again.....oh well won't be the last time. How's it going there pank, they gave some of your allies names the boot for acting stupid over on AC I see....kind of miss someone acting stupid for us over there with cast iron forging facilities and schedule 80 all thread rod ideas.

On the subject of flywheels, it only takes a slight, I mean very slight amount of additional power to rotate a heavy one vs a light one at a particular speed. The more mass that can be contained in the outside diameter of the flywheel the better. If 2 weigh identical on the scale, the one with the lighter center and heavier outside will offer more inertia.

If I am running an unlimited RPM engine, I want to build it so that it will accelerate until the load hits it, at this point the flywheel is going to come into play. I'm going to make it as heavy as possible or practical. This heavy flywheel is also going to help get the tractor off the line by not letting the engine drop so far to get the load rolling. It's harder to accelerate that heavy flywheel, but there's lots of time for the engine to do it.

If I'm making one for a governed RPM tractor that is going to be pulling in some paced class then I'll build a light flywheel. Lets just say you are in a 4mph class and staying low in your RPM range to maintain the pace, as the load comes on and the tires slip it's nice to be able to accelerate the engine slowly to maintain that pace. At a time when the engine is already working hard to maintain it's speed, the additional weight of the flywheel is working against what you are trying to do.

Of course it makes a difference how long it is between the "impulses" of the cylinders firing. A 2 cyl deere with an erratic firing impulse needs more flywheel inertia than a 4 cyl that has an impulse every 180 degrees of rotation, actually you have less than the 180 as the impulse lasts for several degrees. A 6 cyl has closer impulses but there is still a dead spot. Look at a v8 and those engines that race in circle track, the small diameter and light flywheel clutch assemblies that are needed to give them off the corner acceleration. Where that V-8 will have a heavier and larger diameter flywheel when put into a pulling application.

On my low torque high rev engine I want the heaviest flywheel package I can make work. On my high torque governed RPM engine I want a light flywheel, I just need enough to absorb the impulse action and carry it a few degrees until the next one hits.

 

[Anonymous-0]

(quoted from post at 07:48:33 01/04/14)
It's to bad that his carb issue has caused ML to show his ignorance once again.....oh well won't be the last time. How's it going there pank, they gave some of your allies names the boot for acting stupid over on AC I see....kind of miss someone acting stupid for us over there with cast iron forging facilities and schedule 80 all thread rod ideas.

On the subject of flywheels, it only takes a slight, I mean very slight amount of additional power to rotate a heavy one vs a light one at a particular speed. The more mass that can be contained in the outside diameter of the flywheel the better. If 2 weigh identical on the scale, the one with the lighter center and heavier outside will offer more inertia.

If I am running an unlimited RPM engine, I want to build it so that it will accelerate until the load hits it, at this point the flywheel is going to come into play. I'm going to make it as heavy as possible or practical. This heavy flywheel is also going to help get the tractor off the line by not letting the engine drop so far to get the load rolling. It's harder to accelerate that heavy flywheel, but there's lots of time for the engine to do it.

If I'm making one for a governed RPM tractor that is going to be pulling in some paced class then I'll build a light flywheel. Lets just say you are in a 4mph class and staying low in your RPM range to maintain the pace, as the load comes on and the tires slip it's nice to be able to accelerate the engine slowly to maintain that pace. At a time when the engine is already working hard to maintain it's speed, the additional weight of the flywheel is working against what you are trying to do.

Of course it makes a difference how long it is between the "impulses" of the cylinders firing. A 2 cyl deere with an erratic firing impulse needs more flywheel inertia than a 4 cyl that has an impulse every 180 degrees of rotation, actually you have less than the 180 as the impulse lasts for several degrees. A 6 cyl has closer impulses but there is still a dead spot. Look at a v8 and those engines that race in circle track, the small diameter and light flywheel clutch assemblies that are needed to give them off the corner acceleration. Where that V-8 will have a heavier and larger diameter flywheel when put into a pulling application.

On my low torque high rev engine I want the heaviest flywheel package I can make work. On my high torque governed RPM engine I want a light flywheel, I just need enough to absorb the impulse action and carry it a few degrees until the next one hits.

Since you asked I am doing verry well thankyou for asking . I see your learning alot from getting a hold of one of barneys engines to disassemble. you going up to jamisons for the airflow seminar. To add to flywheel it actually matters to what the tire height and weight is. Even a stroker big block with a 4500 stall can need a heavy flexplate if the slicks on the dragster are tall jm2cents

 

[buickanddeere]

(quoted from post at 15:37:33 12/31/13)

(quoted from post at 20:18:15 12/30/13) So- you're saying a 1000# wheel takes NO MORE hp to turn than a 100# wheel???!! Heavier the wheel, the less power remains to turn the axles. Period. Maybe only a fraction of a hp but it's a fact. Take a tire off your wife's car & push it across the yard. Now a semi tire. Hmmm....

A heavier flywheel gives you more torque.....since going to a heavier, steel flywheel on my G the tractor lugs way better.

Contrary to popular belief the average torque is absolutely identical with the light or heavy flywheel.
The heavy flywheel however delivers the torque much smoother with lower peaks and higher valleys on a graph.