Light flywheel

iH welker

Member
How will a lightened flywheel affect the pulling of a farmall M ? For the better or will it need the rotating weight on a stroker!!
 

Light one would let you put a few pounds more out on the front...otherwise, not much of any difference..the flywheel don't "Pull" anything..it only keeps the engine turning over at Idle and Maybe help get the LOAD moving from a stand-still.
 
At the rpm range you're probably going to be running it's not enough to matter. Lighter assemblies are better at high RPM, that's where weight really eats horsepower. At 2000ish it won't matter.
 
go to the drag strip and watch cars with very little flywheel weight,ask some pullers that had to get a "NEW" heavy one back.A wheel in motion tends to stay in Motion,kunfucious saeth !!!!!!!!!!!!!
 
(quoted from post at 19:44:43 01/09/17) How will a lightened flywheel affect the pulling of a farmall M ? For the better or will it need the rotating weight on a stroker!!

A flywheel requires a power input from the engine to cause an increase in RPM. Conversely the flywheel must return power to the engine to cause a decrease in RPM. Typically the engine reaches maximum RPM at the start of the pull when it is lightly loaded - the flywheel has stored power at this point. As the engine is lugged down at the end of the pull the flywheel is returning that power to the engine. No power is consumed or exchanged without an RPM change. As previously posted this power exhange would be small considering the flywheel sizes and RPM range typically used in tractor pulling.

Typically larger engines use larger flywheels. However, unless you are going really big the OEM flywheel should run the engine fine.

To effectively return large amounts of power from a flywheel one would need some sort of variable transmission between the engine and the flywheel. At the beginning of the pull the engine would spin the flywheel to a very high RPM (say 10,000 + RPM). At the end of the pull the transmission would return the stored power back to the engine by rapidly slowing the flywheel. A flywheel spinning at high RPM makes a big mess if it should break - so this is one of those don't try at home deals!
 


NOPE...NOT at the Drag-strip...!!

That LIGHT flywheel absorbs LESS energy, allowing the Engine to wind up much Faster..allowing the vehicle to run Lower ET's..

At the "Pulls", it all depends on what you got..some want and need light, others like Heavy..doesent much matter, the engine need not change RPM all that much..

IF ya don't have enough motor, you WILL need a heavy flywheel to start the sled...
 
I would get a new flywheel for a M. Might want to turn it hard someday! I was told to get a heavy flywheel for my 2 cyl detroit, because they have very little low end torque. So I cut 35lb off it. Only thing I can tell is revs up faster and governors hunt at full throttle. Some 4x4 pulling trucks do run very heavy flywheels. My friends race modified. Their flywheels are about 8" with a cone clutch. Starter is on transmission. 800 plus hp Ford 355 cu.
 
My experience with a large cubic inch "M"
When we went to a steel flywheel with a double disc sfi clutch, we noticed the tractor reved up faster and made the governor a lot more responsive, and we never noticed any difference with lugging ability of the tractor. Of course we only run 20% over on rpms.
Would have been nice to dyno the engine both ways and see what the differences really was.
 

A flywheel requires power to speed up and must give up power to slow down. No power exchanges at steady state (without a change in RPM). If you dyno test with a light and heavy flywheel the steady state HP should be the same.

As noted with a light flywheel the engine will accelerate faster and the governor may be affected.

Before the ORC (over running clutch) for those who bush hogged with tractors that did not have an independent PTO (for example an 8N Ford) the flywheel effect was very apparent. The spinning blades of the bush hog acted as a flywheel and the engine needed to work to bring them up to operating speed. At operating speed the governor would close and the engine would loaf along, over coming only bearing friction and wind resistance from the spinning blades. Now push in the clutch to miss the fence and the tractor did not stop, the spinning blades would continue to push the tractor.

In tractor pulling the flywheel effect is still there but the sled is slowing the tractor. Since the sled is slowing the tractor the flywheel effect is not noticeable to the operator. As this writer and others have posted the effect is likely small compared the tractor HP. However, it does increase as the size of flywheel, the square of the RPM level and the rate of change of RPM.
 
(quoted from post at 19:44:43 01/09/17) How will a lightened flywheel affect the pulling of a farmall M ? For the better or will it need the rotating weight on a stroker!!
One of the important functions of the flywheel is dampening harmonic frequencies. As the crankshaft stroke increases, dampening becomes more important. If a harmonic balancer is used on the front end of the crank and the rotating assembly is balanced, then some flywheel lightening can be done. The deal is, we're doing things to these old engines that makes them a ticking time bomb. Summer before last, I saw a professionally well built M break a forged crank, so with the best of everything, there are no guarantees. Just lightening up a flywheel without taking other precautions may not be a long lived idea.
 

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