Minimizing "HUM" from Athearn BB


ken_23434

ken_23434

Member
I recently got a new Athearn BB SW-1500. The item is "new" although I am sure it has been sititng on a shelf somewhere for a long time.

Based on info I read on this site, the first thing I did was take it apart, clean and inspect the gears, reassembled everything and hardwire the motor and trucks. I wanted to do the "burnishing" of the gears with the Pearl Drops, but I forgot to get them.

I did not see any issues with any of the gears while I had it taken apart.

I put it on my track for a test drive, and the first thing I noticed was that it had quite a loud "hum" to it as it was running. It was running on DC, not DCC. It did not sound like something was broken, it just sounded like the motor was really out of balance and vibrating. Other than the noise, it ran smooth and was able to run fairly slowly. My other engines are 2 Proto-2000 units, so that is what I have to compare the running and noise to.

It was pretty late at night when I gave it a test run. I was pretty tired and did not do a lot of experimenting. Although, I did pul one of the drive shafts off, and it seemed to get quite a bit quieter. Of course, it might just have been "half as noisey" since there was only half the running gear to make noise. There was no visible movement (vibrations) of parts while it was running.

I have seen a lot of replacement or upgrade parts from Proto Power West. I am not sure if those power trucks and shafts are an "improved" design, or just replacements.

Is this "hum" typical of these Athearn engines?

My motor has the brass flywheels and the plastic shafts. From one thread on here, I think it is the 3rd generation of the Athearn Drive system. I do not think it is the hex drive. My shafts had 2 pieces that protruded from them (looked like shovel heads) that fit with a matching type in the flywheel. My understanding is the hex drive would have a 6 sided piece, similar to a ball and socket design.

I noticed that it appears the motor is sitting higher than it should be. The shafts point down as they go from the flywheel to the trucks. From pictures I have seen, this is "normal". I would think the best thing for the universal joints is for the shaft to be horizontal.

I only put a drop of grease on the gears based on what I read on a "tune-up" thread I read. Would more grease minimize the noise?

I thought about filling the cavilty below the motor with RTV and positioning the motor lower in the chasis so the shafts were more inline. I thought the RTV motor mount would help isolate any noise from the motor and the inline shafts would make it better for the universal joints and possibly eliminate and noise from them. Although, I am not sure if the reduction in the air gap under the motor would lead to heat issues. I am not sure how much torque is exerted by the motor and if the RTV mount would hold up. I have seen double sided tape recommended for mounting replacement motors.
 
im not an expert with BB atherns but from my experince if gear lube does not help its likely the motor vibrations.
I know some guys at my RR club will add foam to the insides of the shell to absorm some of the vibration. some also have added diffrent "Home made motor mounts" IMO I think that the vibrations are from the motor and it has more to do with the noise than the gears do
 
OK, thanks for the input.

I kept seeing things about not using too much lube on the gears and bearings. From the factory, they usually come with way too much lube according to what I read. So, I am reluctant to slop a lot more grease into the gearboxes for fear of causing other problems.

Maybe I could just pull off both shafts, give it some power and see if it makes noise or not. That will tell me if it is the motor or not.
 
ken_23434 said:
OK, thanks for the input.

I kept seeing things about not using too much lube on the gears and bearings. From the factory, they usually come with way too much lube according to what I read. So, I am reluctant to slop a lot more grease into the gearboxes for fear of causing other problems.

Maybe I could just pull off both shafts, give it some power and see if it makes noise or not. That will tell me if it is the motor or not.
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Alot of lube will just collect dust. From what I remember the BB athern motors spin freely with little noise. the problem is as soon as the shell is added it multiplies any noise or sound vibrations by 10! simmilar to how quiet a loco with a sound unit is with the shell remved and then how loud it is with the shell on. the shell acts as a baffel and collects all the noise and makes it seam louder than it really is. Trent
 
My engine does not have the shell on it yet. :eek:

I am going to paint and decorate it at some point. I was just giving it a test drive without the shell when I noticed how loud it was. I wonder how much worse it will be with the shell on it.

The concern with excess grease and the dirt is why I only put a "drop" of grease in the gearbox. I am not sure if my "drop" is the same as the "drop" the author of the article uses.
 
ken_23434 said:
My engine does not have the shell on it yet. :eek:

I am going to paint and decorate it at some point. I was just giving it a test drive without the shell when I noticed how loud it was. I wonder how much worse it will be with the shell on it.

The concern with excess grease and the dirt is why I only put a "drop" of grease in the gearbox. I am not sure if my "drop" is the same as the "drop" the author of the article uses.
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a drop of lube is all you need:)
 
Try some 2-26 on the commutator where the brushes contact. I have done that on several BB Athearn locomotives and has seemed to quite the motor noise. 2-26 is an electrical lubricant, not only does it lube, it conducts electricity and drives away any moisture also. You can pick this stuff up at Home Depot in the electrical section, its in a small blue can with big white letters and only costs about 5 dollars i think. Also another good use for 2-26 is using it after cleaning track, just put a small amount on the rails about the length of a locomotive and run a train, works great on a layout with DCC, I did that on my friends layout and we go months without cleaning track. When you run over the stuff with a locomotive it spreads a film on the rail head that turns dark but it does not hurt electrical contact.
 
I will try that out. I would never think the commutator could cause a noise. The better conductivity sounds great.

Any concern with it shorting out the commutator segments, though?
 
I've found that automatic transmission fluid is the best lube for Athearn BB gearboxes. Make sure it's Dextron III so it won't damage the plastic. A drop in each gearbox and on the universals has quieted down most of my older engines. Works good in new engines too. :)
 
UP2CSX said:
I've found that automatic transmission fluid is the best lube for Athearn BB gearboxes. Make sure it's Dextron III so it won't damage the plastic. A drop in each gearbox and on the universals has quieted down most of my older engines. Works good in new engines too. :)
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OK, thanks. I have Hob-E oil and grease that I used. Dextron would have saved me some time, since I already had that in the garage. The recommendations I kept seeing were for Labelle products, but the LHS doesn't carry them. I guess a phone call to them would have saved that trip.

I was out in the train room last night working on something else, but I ran this engine while I was in there. Maybe it's all in my head, but I think it seems quieter now. It might just be a break in period thing. The hum is "manly", if that would be a good description. It sounds like the engine is real powerful. It would be worse if it sounded like something was broken or it was a "toy engine" sound. It's almost like a growl coming from a muscle car with a good exhaust system on it.
 
Ken, that "growl" is characteristic of Athearn BB engines. A run in period does help to reduce the noise but the gear boxes have always been a little loose, which seems to cause the growl. One of the the things you can do is drop all the gears out and inspect them. You'll probably find a few that have some small burrs on the teeth. File those flat, clean everything off with some alcohol, reassemble, and then try a drop of ATF in place of heavier stuff like grease. It's the best method I've found of making my old BB's run quieter.
 
Ken, with Jim's valuable advice, be sure to use the fine needle files on the gears.
One modeler used a metal file that was too large and filed down a couple of gear teeth.:mad:
Mikey
 
Mikey, I should have added that caveat. It's easy to do too much filing with the wrong size file and then that thing will really growl! :)
 
Hum

Also keep this in mind: Older Athearn BB drives are not ever going to be as quiet as Proto 2000 drives. I have nothing against the old BB models. They're built like tanks, run forever with minimal care, and are just about bullet proof. I am still using quite a few for projects. Make sure your motor mounts are fully seated, & you have a clean commutator. Mounting the shell may cause a resonance (make it louder), or maybe not. Short of an aftermartket motor, the cleaning deburring, and lubing are about all you can do. One more thing: Are the flywheels brass or gray?
 
They are brass.

I took it apart and cleaned everything with alcohol as soon as I got it. I checked the gears for any flash or any other signs of problems. I think I should have had some sort of magnifying glass to help with the inspection, though. I did not see anything. I did expect to see some flash or burrs on the gears from what I read.

By cleaning the commutator, do you mean taking emery cloth or very fine wet/dry paper and "polishing" it? Since this engine is brand new, I was reluctant to doing that. I thought any abrasive cleaning like that would shorten the life and would be more appropriate after it had some use. I am not really sure if that is appropriate or if I should have polished it to give it a "good start".

I really appreciate everyones advice and suggestions.
 
No, not emery cloth! "The finest 3M Crocus cloth is the roughest thing you'd want to use, though all I typically do is take a cloth pipe cleaner (Not the synthetics!) soak it in Xylene or lacquer thinner and clean the crabon off. Take an X-acto with a #11 blade and run the tip of the blade through the slots between segments of the commutator and clean out any carbon that gets in there. Then just a drop of "Conducta" (by Aerocar) on the commutator to lube the brushes. Even new motors have this gunk in them.

A "Hum" to me indicates an electrical issue, where a "growl" indicates gear issues. Also, I shitcan the contact strip that runs between the top of the motor and the trucks, and replace it with a hard wired connection.
 
I hard-wired the engine before I ever ran it, based on info I got from this site.

I don't know the difference in emery and crocus cloth. The tune-up page I read said he used 1500 grit wet-dry. I don't know the "grit" on crocus or emery cloth. I will check the local hardware store for the crocus cloth. I have heard of it before, (and I am sure I have seen it) I just don't know the difference in it and emery, or the really fine sand papers.

Anyone have ideas where to add weight to the SW-1500? I read to add as much as you can fit, but I am having issues finding space (other than the cab) for my digitrax 123 series decoder.

My idea (maybe not original) was to have the side frame for the trucks made from lead. That way, you have weight added as low as possible, without taking room from the shell where you might want to have a speaker, decoder etc... Of course, I am not going to make those frames. I was hoping one of the custom detail suppliers offered something like that. Hmmm... maybe I should not have posted my idea for someone else to go make $$ from. Well, if you take my idea and get rich, send me a free set of truck frames. :)
 
1500 grit cloth will do nicely! Not much room to add lead and a decoder! I find mine don't need any additional weight. They will pull 10-15 cars on level track without any trouble at all. How many cars do you need to pull? If you want to pull a long train with them, use two or three as the prototype did. Just a suggestion! ;) BTW, I changed out the Athearn sintered wheels with Jay Bee wheelsets. Better conductivity, not such crud magnets! Also not that expensive!
 
Espeefan said:
1500 grit cloth will do nicely! Not much room to add lead and a decoder! I find mine don't need any additional weight. They will pull 10-15 cars on level track without any trouble at all. How many cars do you need to pull? If you want to pull a long train with them, use two or three as the prototype did. Just a suggestion! ;) BTW, I changed out the Athearn sintered wheels with Jay Bee wheelsets. Better conductivity, not such crud magnets! Also not that expensive!
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Do you have a part # and website for those wheelsets? I have looked up a few other brands I have seen recommended, but I don't know what part # is the correct one.

The advice I read about adding as much weight as possible stated you would get less crud buildup with heavier locos. Plus, I want the better wheels so I won't have the conductivity issues and such.

I won't be pulling much with it. Likely, it will be just switching out tank cars for a planned chemical plant that will eventually exist on my layout. I will probably end up with a shipping terminal too, so some sort of freight cars at warehouses / intermodal sites.
 
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