# Athearn drive - Brass Flywheels Better Than Steel??



## Eddystone (Sep 2, 2014)

Hi,

I have a few Athearns with the dual brass flywheel drive. They are not Swiss watches, but they run just fine for me, and I'm on a budget.

Do the older Athearns with the black motor and steel flywheels run as well as the later ones, or was the later drive a big improvement?


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## gator do 65 (Jan 27, 2014)

I would think the brass is better balanced than the steel and the motors are far better than the old style. As with most thing's technology improves how well they work!


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## Old_Hobo (Feb 20, 2014)

More discussion (from Oct. 03) of this here:

http://www.modeltrainforum.com/showthread.php?t=25149


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## Mister Bill (Jan 30, 2014)

I just went down that road.

All of my locos are 25 years old or so, but I always took care of them and they were satisfactory. But, I got the bug to upgrade.

First, you have to send Athearn an e-mail listing each model you are changing. A couple of days later, they will send you a part list needed for each model - GP9, F7, etc. A couple of weeks later, you will get your parts. Most parts are not interchangeable from model to model, except the motor. You also have to change out the connector and gear box. I cannot think of the proper names.

Bottom line, one unit cost me $52 with shipping and all, and I would say that it is about 5% quieter and smoother than the original. 

I think the new motors might draw less current, but I don't understand electrickery that much.

Unless you have a real growler or the engine is in bad shape, you may just be going sideways. The growl might be coming from the truck gears and not the motor, which is another matter. Also, the new motor wires up differently, and that gave me a fit for a while.

It is not a quick fix and it is expensive. You might be better off with a down payment on new engine. I did it because I liked my old shells, which was important to me. I might do one more, but probably not.


Bill


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## ggnlars (Aug 6, 2013)

The brass fly wheels could be better balanced. The round motor is a beast. It has a 16 volt stall current of over 3 amps. The blue box rectangular motor that had the brass fly wheels had a corresponding stall current of slightly over 2 amps. 
The more modern motors have brought that down to 1.2 amps. The modern motors are quieter. The splines have less vibration. 
They are designed to be sound loco's. In general they do not pull as well as the older models. 
I have been doing a lot of testing on all sorts of HO engines. See my blog for some interesting results.
Larry
www.llxlocomotives.com


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## Eddystone (Sep 2, 2014)

Bill, thanks for your input. I wasn't considering remotoring a "steel" chassis into a "brass one" as I can see that it would not be economical. I'm just considering the purchase of some used Athearn engine from either eBay or a train show, and I wondered how much difference there was between the two designs since I haven't had both to compare.

At this point, I have read enough to know what to do. For me it makes sense to choose the "brass" chassis if I buy a used Athearn engine because 1) it may be somewhat smoother in operation, (2) the newer motor draws less current in general, and (3) it will hold its value longer because future buyers with DCC will find it a more suitable choice for conversion.

We are all at our own particular place on various spectrums in this hobby. Some are DC analog while others are DCC. Some have more money to spend and can afford more modern or more detailed models. Some have very high standards when it comes to noise and smoothness while others don't mind them sounding like the electric trains of old.

I just like to tinker with the mechanism and can usually get it to where I am satisfied. I have to admit that I just like to watch them run. I like them to "feel" realistic but don't have extremely high standards about being fully prototypical. I sort of nod in that direction, but I sort of squint a bit and use my imagination to see all the right valves, hoses and rivets.

Thank you to all who responded!

Glen


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## Eddystone (Sep 2, 2014)

Thanks, Larry!

Your site looks very interesting. I'm going to start reading now!

Glen


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## hannamet (Dec 1, 2012)

*flywheel balance*

Guys, the metallic material used for the flywheels does not effect the balance as long as we are talking about modern metals. Most modern steel and brass bar stock is sufficiently homogenous for this purpose. Steel is almost as heavy as brass, so they will be similar. The effectiveness, flywheel effect, of the rotating mass IS affected by it's weight, (and shape), so don't use anything much lighter than steel. Athearn figured out that brass was sexier and didn't rust! Stainless would be even prettier!


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## Mr. SP (Jan 7, 2015)

*Flywheels*

The original Athearn flywheels were cast iron. Since they were cast instead of machined they were not round and added to rough running. The brass flywheels are far superior. It might be possible to just replace the cast flywheels with the machined brass ones


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## hannamet (Dec 1, 2012)

*cast vs machined?*

Casting is a rough approximation, unless it is a precision casting process, which it wouldn't be considering the value of an Athearn locomotive, so I'm confident the cast iron or steel used was machined versus being used in the as-cast condition. But I admittedly do not recall ever seeing an early Athearn flywheel made of steel or iron, so I cannot say absolutely, without seeing one, if they were machined or not. Anyone have a picture of one?


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