# Flywheels........How do you remove them?



## rsv1ho (Oct 16, 2019)

These (Athearn?) flywheels came on a couple of recently purchased Varney F3's. Looks like they are built right into the small end pully. The is a hole in the outer end but a flat bladed screwdriver or Philips has no effect. Any ideas?


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## Lemonhawk (Sep 24, 2013)

Do the motors no longer work? I think what looks like it might be a screw to loosen the flywheel is really a balance slot and not connected to flywheel removal. Probably takes some kind of puller. Even if you could pull it, it does not appear that a 3 sheave pulley replacement would match wheel pulley. The close-up picture of the motor looks like the pulley on the motor is damaged, is that what your trying to replace?


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## rsv1ho (Oct 16, 2019)

Thanks for responding.

The motor works fine, takes awhile to get the flywheel spinning up to speed, but that's normal. 

This is curious. Looks like the previous owner made some major mods to the locomotive itself. Whomever did it, it's nicely done. Looks like the low speed end of the pully is part of the flywheels backplate. Normally the pully is soldered on the armatures shaft. These originally came as kits.

It looks like the flywheel has an outer shell with two ends inserted, but there is no evidence as to how they are bonded.


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## Severn (May 13, 2016)

Someone in know can correct but "a puller" if it's friction fit could be right.

Here's a homebrew solution I dug up.






There may be better options or tools. Mat


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## rsv1ho (Oct 16, 2019)

Thanks, Found one on ebay, 20 bucks, I will make my own.

But this is a futile adventure. The person that did this mod didn't do their homework. The pulleys don't align and the wrong ratio was used. I used a rubber band as the drive mechanism as the factory coiled spring belt was not included. Poor substitute, the rubber band rubs on the pulley, but amazingly this thing moves albeit at glacier speed and nothing that I would have on my layout. 

Only solution is to remove the flywheel and replace it with the factory Varney pulley, probably impossible to find.


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## flyboy2610 (Jan 20, 2010)

I admire your dedication to this project!


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## Lemonhawk (Sep 24, 2013)

google "removing athearn flywheels", talks about just wrapping the motor in cloth and pulling real hard. I would be surprised if this worked. read and see if it makes any sense


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## Severn (May 13, 2016)

It seems unlikely.


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## rsv1ho (Oct 16, 2019)

Thanks, I just googled_ Athearn Flywheels, I _didn't go far enough. _







_

I think this will work with some modification. I only have to pull the flywheel back about 1/4" to align the pulleys. Then I can go to the high speed pulley on the array. I just hope the armatures shaft is long enough.


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## Severn (May 13, 2016)

To me the weight (the flywheel) is gripped only. The center pin/shaft is then pressed back through it. That's it. Unless the thing is welded on or something... It seems to me it ought to budge... Now maybe someone might consider some of that penetrating oil stuff. Not sure that's applicable or even works. My experience with this kind of thing more involves unmovable bolts or nuts. In that case a longer lever has always solved it. Not quite the same problem here. Except it all has to be not wiggly so the end of the shaft gets the force.


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## rsv1ho (Oct 16, 2019)

The flywheel rotates around a stationary center tube friction attached to the armatures shaft. You can hold the armature in place and rotate the flywheel. Once up to speed inertia tends to dampen the inherent electrical instability of the motor offering smoother operation of the locomotive. It least that's my understanding. I'm not in favor of the thing but I'm going to make it work in the Varney. If it works for Athearn, why not. 

I will have to switch to the B units frame as it offers more room for the flywheel. North/South. The previous owner had to construct a ridged platform for the motor to keep it from rotating with the drive unit. If it rotated as it goes around curves the flywheel would hit the sides of the locomotive. Points for that, but major points off for execution.

I will have to be careful not to damage the armature, those are getting hard to find.


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## Severn (May 13, 2016)

Eh, so the flywheel is on a kind bearing?


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## rsv1ho (Oct 16, 2019)

Yes, and it's very smooth. The whole exterior barrel is free to rotate. I'm afraid if I try to pry it off it will damage the brass enclosure for the oiling pad. 

If I get it off and cannot align the pulleys I may have to have a machine shop mill me a replacement three step pulley as original Varney pulleys seem to be non-existent..


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## gregc (Apr 25, 2015)

my dad said in their shop they would chill pins and heat the metal with the holes before inserting the pins making it extremely difficult for the pins to fall out or be removed


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## Severn (May 13, 2016)

Ok possibly delete all previous comments!

So I'm looking at the picture again. Tell me if this is right. The flywheel is on the motor shaft but "floating". The motor itself does not spin it. Instead it indirectly spins by the pulley below it attached I believe to the wheel assembly... ?


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## rsv1ho (Oct 16, 2019)

You got it. 

The motor starts at speed, but the flywheel starts slowly then gains revolutions eventually catching up speed to match the motors shaft. Has a dampening effect. 

How do you edit posts? I see no "edit" icon...…………......


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## Severn (May 13, 2016)

The 3 dots upper right brings up a pop up option. After you post. You edit and report yourself.and just report others. The report is useful if trolls appear... Although here, not so much or any problem.

As for the athearn drive... Ok I think I get it. Slowly start, slowly stop. I guess in DCC land they've removed the need because of the motor control. 

But how to get it apart. Did you try contacting athearn? I'm poking around their website without much luck ...


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## Severn (May 13, 2016)

Maybe you find a parts diagram here...
What is that kind of drive called?



Athearn Information and Diagrams - Literature Page 6


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## rsv1ho (Oct 16, 2019)

Thanks, I have that site on my favorite places.

It's call Hi-F (high friction) referring mainly to rubber band drives. Varney also offered them but this one has a coiled spring belt that is much more efficient. 

Thanks for the que on the edit feature, I couldn't figure it out.


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## Severn (May 13, 2016)

Is it this? It doesn't quite look the same.


athearn hi-f drive - Google Search


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## Lemonhawk (Sep 24, 2013)

On the original Varney drive doesn't the motor rotate on the trucks? I worry that with a fixed motor with a belt drive would constrain the trucks such that they will not rotate around curves properly. Also you seem to imply that the counter weight is not fixed to the motor shaft, but that it somehow rotates independently, I've never seen that. But then I have exactly 2 Athearn Diesels (a PA-1 and a PB-1) and the counterweights on those units are fixed to the motor shaft. Should be interesting to see what you come up with!


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## rsv1ho (Oct 16, 2019)

Different but the same principles apply. Looks like dual smaller flywheels with one on each end. I have heard good things about the Ahearn's, I have a few but none with flywheels.


Lemonhawk said:


> On the original Varney drive doesn't the motor rotate on the trucks? I worry that with a fixed motor with a belt drive would constrain the trucks such that they will not rotate around curves properly. Also you seem to imply that the counter weight is not fixed to the motor shaft, but that it somehow rotates independently, I've never seen that. But then I have exactly 2 Athearn Diesels (a PA-1 and a PB-1) and the counterweights on those units are fixed to the motor shaft. Should be interesting to see what you come up with!


No, on the unmodified Varney the motor, drive unit, and trucks are all fixed together and rotate as one on a pivot. On this previous owner modified Varney the motor is fixed on a stage and does not rotate with the drive unit or truck. Necessary to avoid the bulky flywheel to hit the sides of the shell during turns. 

A concern of mine also that the fixed motor will limit the travel of the truck, but there is a lot of give with that coiled spring so we will see.

My modified press worked great. It allows precise movement. I backed the flywheel off the armatures shaft about an eighth inch which should align the two pulleys but we will see. Also media blasted the frame and the trucks. I usually disassemble these before hand, but that's not necessary. I will disassemble both and clean and paint later.



































.


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## Severn (May 13, 2016)

So it's just the shaft of the motor and the flywheel that form the bearing or is there another sleeve? I guess I don't quite see how the flywheel stays fixed from moving on the shaft.


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## rsv1ho (Oct 16, 2019)

Curiosity got the best of me and I took it apart. It just snaps back together, no problem.






























The armatures shaft is soldered to a mass that has two independent weights that rotate outwards contacting the brass flywheel causing it to spin. Pictures are worth a thousand of my words.


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## Severn (May 13, 2016)

Wow. Well it's a little hard to see exactly how it's constructed. It's definitely not a solid flywheel pressed into the motor shaft... 

Its kind of interesting to me at least to compare that, the "analog solution" against the DCC motor control digital solution ...


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## rsv1ho (Oct 16, 2019)

Yes, inertia causes the two counterweights to expand outward contacting the drum causing it to spin. I can't see the benefit in this situation, but I'm going to keep it if it works. Right now the other working one is just to slow on the track. I don't think the PO ever got it to work, he had it wired wrong from the beginning.


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## Severn (May 13, 2016)

one thought is if each drum is not calibrated to some similar criteria, each will behave differently.


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## Lemonhawk (Sep 24, 2013)

It's called a centrifugal clutch. I know its not on the 2 different types of Ahearn motors I have. A surprising find!


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## Severn (May 13, 2016)

i've seen this kind of thing elsewhere but i can't recall where, not on a model train.


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## rsv1ho (Oct 16, 2019)

Lemonhawk said:


> It's called a centrifugal clutch. I know its not on the 2 different types of Ahearn motors I have. A surprising find!


Thanks, that's the term I was searching for in my muddled mind. Got several examples on my model cars and air tools.


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## rsv1ho (Oct 16, 2019)

Got everything cleaned up, and it runs. Just not great. Rubber band slips and nothing that I would put up with. So I got on ebay and found a motorized truck with both pulleys and a coiled spring drive band for $20, far less than what a machine shop would charge me to make a couple of pulleys. The two pulleys will replace the two flywheels and return these two locomotives back to factory.


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## Severn (May 13, 2016)

You need a tensioner and something beefier for the rubber band maybe.


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## Lemonhawk (Sep 24, 2013)

A far superior fix! You could have put a lot more money into the fixed motor only to have it be constrained to very large radius turns!


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## Jscullans (Jul 8, 2019)

I would like to get ahold of one of those to tear it apart to better understand it. I can get the idea that the flywheel would be used to keep the motor spinning but if it was floating that wouldn’t help much unless it was on some form of a clutch that only engages when the motor looses current. Seems to me like that flywheel isn’t doing a whole lot and that motor just runs really good


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## Severn (May 13, 2016)

There's a pulley off the wheels to the flywheel. So the motor makes the wheels to round, the pulley spins up the flywheel. That takes a little energy. Then to slow down the flywheel resists. Or that's what I get...


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## Lemonhawk (Sep 24, 2013)

Here's how I think it works. The motor shaft is fixed to the pulley (that goes to the wheels) and to the centrifugal clutch. As the motor starts to turn, the clutch starts to engage the flywheel. Faster it turns the the more the flywheel is connected to the motor shaft. Then as things slow down the clutch will eventually release the flywheel.


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## DOOFUS (May 20, 2013)

rsv1ho said:


> These (Athearn?) flywheels came on a couple of recently purchased Varney F3's. Looks like they are built right into the small end pully. The is a hole in the outer end but a flat bladed screwdriver or Philips has no effect. Any ideas?
> 
> 
> Could this possibly be the Kadee snap on Fluid drive system where you "somehow" Added various weight oils to change the momentum?? Never Never saw anything like this.
> ...


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## rsv1ho (Oct 16, 2019)

These have weights that I think expand with speed and contact the outer barrel. When I have the time I'm going to take one completely apart and find out exactly what's going on. 

Stay tuned.


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