Athearn Engine mods?


AyTrane

AyTrane

Member
Has anyone done any modification to their Athearn engines to make them run quieter? I found a website that had step by step directions, but I wanted to do some research to see if anyone else had any luck with anything to make their locos run quieter before I went ahead and overhauled one of my great running (but sometimes noisy) engines.


Link to Athearn Tuneup:

http://www.mcor-nmra.org/Publications/Articles/Athearn_TuneUp.html
 
No, but after reading that whole section from that link I'm going to tackle about 5 of mine. I have some real slow & noisy Athearn engines that's needed a tuneup for quite a few years. I have one torn down for some drastic wiring changes. I printed all 14 pages of that article & will be starting tomorrow or soon on an SD40-2.
Thanks for that link. He really gets into the fine points of rebuilding all these engines.

Larry
 
Well yes I've done mine but a lot different than that site
Here's another site for you to read (add to the confusion), however I don't seem to have the link where I got some of my ideas.
The lubricant I use, I got from Radio Shack, I'll get the name of it for you tomorrow.
Those rubber motor mounts are a source of trouble, I threw mine away and added phenolic strips (plastic will do) where the rubber mounts were. I drilled holes centered and used 3 mm brass screws to mount the motors. 2-56 screws will work also. theres enough room on the motor base to drill and tap for the screws.
Electrical.png
Sorry this is the best I can do for now,
111-1163_IMG.png
where I wired directly to the truck and if you click on the link to my site you'll find a bit more.
Sorry have to go the dog wants out
Cheers
Willis
 
Good luck Larry, let me know how it turns out.

Willis, what benefits do you get from hard mounting the engine to the chassis? I have three SD45's and three F7's that could benefit from a mod. I'm really interested in doing this, but I don't want to ruin any of my engines that are running perfectly (other than the noise they have always had).
 
The Athearn rubber motor mounts deteriorate over time and allow the motor to flex. which allows the gear train to go off center can contributes greatly to noise and poor running. Willis's solution will work fine if you are running a DC layout but not so good for DCC, since it grounds the motor to the frame. I usually remount mine using silicone adhesive to both hold the motor and isolate it from the frame for DCC. I've just seen an article about using plastic screws to hold the motor, going through a strip of Kapton tape so you'll have both insulation and a firm mount for the motor. I've ordered some of the screws so we'll see if they really work.
 
Jim,
How about those plastic screws that come w/Kadee couplers? Very seldom I ever use them, but, now I might w/the conversions.

Larry
 
Larry,
The web site looks like pretty standard stuff. I probably go a little overboard with polishing the armature. I spin them up in a drill and hit them with 220,then 320, then 420,1000 and 2200 grit wet papers, finishing up with a regular old pencil eraser for the final finish. I usually replace the Athearn mounts with new Athearn mounts from my LHS. New ones are a lot more supple, heck the old ones usually split anyway when removed. New ones are pretty cheap, and after modifying the bottom clip so it can't touch anymore, why bother with the drilling and tapping or waiting fo Silicone to dry?
I can usually do it all plus add DCC and replace the wheels with nickle silver in under 2 hours. The running difference is amazing!
 
http://www.essortment.com/all/athearnmodeltr_rkec.htm
Hmmm guess I forgot the link :eek:
Jim has pretty well explained (right on) the reason for getting rid of the Athearn motor mounts. There's also suggestions for regearing the Athearns with Ernst gears. In a few words "Don't do it." I did a couple. they had a very low speed and increased noise. I put the locos back to normal gearing, they work fine with a decent throttle. I have MRC Tech II's
I used CA (crazy glue) to mount the two plastic strips on the frame. There are indents in the frame where the rubber mounts sit. I cut the plastic to fit into these. The motors in mine are insulated from the frame in anticipation of going DCC in the future.
Was it worth doing? You bet your booties it was, unless the track is dirty there's no hesitation or hic ups when running, runs as smooth as the baby's bum. Noise, All I can say for sure about that is I think it's much better but I have nothing else to compare it to, besides I'm some what hearing deficient (deaf, there's a lot of frequencies I don't hear)
Willis
 
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One of the problems with a question like this is that there are multiple causes for noise in Athearn drives, and for every cause there are about 20 home remedies, some work better than others. Treating the wrong symptom can be a major waste of time.

The current crop of Athearn RTR (not Genesis) models utilizes the present incarnation of the legendary "blue box" drive. One characteristic of this drive system is extreme inconsistency from one production run to the next, or even one sample to the next off the same production batch.

Most of the vibration and rumble comes from the motor and flywheels. Calling it "gear noise" is a misnomer. If you want proof, just disconnect the main driveshafts and (with the shell back on) rev up the motor and see if you don't hear that same "gear" noise while the gears are not even involved!

Then there's the U-shaft rattle, which has been improved considerably by the new hex-shaft. This design was pioneered by Kato. The plastic shaft has a hex "nut" molded onto the end of it, and the flywheel has a hex-shaped indentation to match. This allows the shaft freedom to pivot but it's a fairly snug fit with fewer parts than the earlier snap-on ball joint. The ball joint is still used at the other end of the shaft.

The shafts are delrin "acetal plastic" and the tolerances are a bit loose, so there can be some "whip" in the shafts as they rotate. Athearn locos have a 12:1 gear ratio, which means the motor turns 12 times for each turn of the wheels so the frequency of any vibration in the motor to worm shaft train is going to be at 12x the wheel rotation frequency.

Athearn's gearboxes are delrin and so are the gears. You can load them up with toothpaste and "polish" them but IMO this is a waste of time - the gears are already loose fitting and don't need lapping or break-in like metal gears would. It certainly won't do anything about the flywheel rumble, which is caused by an imbalance in the motor+flywheel combination and not unlike having an out of balance wheel on your car. The faster you go, the worse it gets.

Ernst gears have been around since the 70s. Not sure if they are still made, or if they'll adapt to all of the current Athearn gearboxes. They use a system of compound gears to turn the 12:1 gearbox into a 32:1. It's an interesting concept, if the gears were of a higher quality it would be more effective. I tried them back 30 years ago and found that they aren't even round... between the slop and the egg shaped gears, they produced an unacceptable lurching motion, and because the motor is turning nearly 3x faster at any given speed, it magnified any flywheel imbalance. I had an SD9 drive set up with Ernst gears and at track drag speed of about 15 mph, it sounded like an empty blender on "puree". I tried the Ernst gears in a switcher, where they would be most logical, and the performance was unacceptable - I've seen rubber band drives with a more steady gait. With the better motors available now, and DCC, Ernst gears are obsolete and they were never consistent enough in their quality to be viable. Of course tripling the gear ratio also creates issues with multi-unit operation... big issues.

IMO the best way to fix a noisy Athearn is to not buy one in the first place. I don't mean don't buy the loco you want, but if you have the opportunity to buy from a dealer, hopefully there will be more than one of what you're looking for in stock. Test run as many as you can, and pick the smoothest running sample to take home. Run the loco at track speed, rapidly crank it up and see how it responds. Don't let the hobby shop guy give you a "creeping" demonstration. Any loco with a binding shaft can "creep" well! You want to get the motor RPMs up and listen for vibration or any rattles. If the loco has a little coasting motion when you shut down, so much the better - this indicates a very free running mechanism and motor. Unfortunately now that Athearn locos are RTR and more finished than in the old bluebox days, the one with the paint job you want may be the only one in stock and the dealer may not let you swap mechanisms - that was another frequent trick back in the days.

The second best way if you do get stuck with a growler is to just replace the motor. If you have a hex-shaft Athearn, you can get a Kato motor with the same hex flywheels. I have just glued the Kato motor to the rubber Athearn mounts. You will need to wire up the new motor. The difference is huge.

Proto Power West also makes remotoring kits specifically for Athearn locos, which come with Mashima motors and brass flywheels that have been manufactured a little more in balance... sometimes I think Athearn just chops up brass rod and drills the ends. But, I've seen some like this that run true, and some of their old machined flywheels that didn't.

I guess it goes without saying to first look for the obvious. Sometimes Athearn diesels show up with a worm clip dislodged or the motor dislodged from its mount, shafts dangling, or something (wire, clip, etc) actually rubbing against the driveshaft. Cracked axle gears are rarely a problem - these are practically a trade mark of Proto 2000's Athearn clone drives however, characterized by a thump-thump-thump sound that matches wheel RPM.

Andy
 
The Athearn locos were designed to provide a decent but cheap entry to serious model railroading. To accomplish this, it was necessary that the locos could easily be assembled and mass produced. Unfortunately the electrical and the mechanical aspects suffered as did quality control because of the requirement, but people with little dollars to spare got their moneys worth and more. True the flywheels are not balanced, the shafts and gears are just so, and if a person wants a perfect running model, well those are available too but at a much higher cost than the Athearns were. To bring an Athearn loco up to the same specs as (? a favorite top line loco :D) would not be feasible for money spent, it would be better to buy a top quality loco in the first place. However a lot of MR enthusiasts don't have the $$ to put out for the best.
Now for those seriously operating on a budget, the Athearn is definitely a decent loco for the price. That said, with a little work and next to no extra cost the running characteristics can be improved immensely, that's all these tuneups do. At the time I started the only models of the MLW C630M were Overland brass. $600 apiece not counting tax; shipping etc. and I needed 10 of them. No doubt a divorce would have been in the works if I had of tried that. However the Athearn U33C and a couple of Tyco shells filled the bill, so for about $120 each I got my fleet. (I've only built six so far and each one gets a bit better)
The gears sometimes do have some little spurs (flash) that should be filed or cut off. To leave them there because the gears can still turn is ok, but a definite improvement will be noticed when they're gone. Running characteristics are improved immensely by replacing all mechanical/friction type electrical contact surfaces with wiring. Stopping the motor from wobbling reduces the binding there for noise reduction. All those things do not bring it to the same level as, say a Proto or PK2 loco but improvements are noticed none the less.
I do agree about the pearl drops (whatever they are) and tooth paste etc., but a lubrication is necessary. What I use is the Precision Oiler from Radio Shack.
It has micro miniature particles of Teflon and Fluon (whatever that is?)
Descript.
-Super slippery lubricant resists dust, does not coagulate, and has no oily residue.
- Unaffected by temp extremes (-51C to +260C)
- Penetrating action frees "frozen" nuts, bolts, locks and bearings.
Anyway doesn't harm plastic so it works for me :)

Cheers
Willis
 
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