I have four of the Atlas U33C / U30C units and all the trucks have an annoying chatter to them. Has anyone else observed this ??? I can’t for the life of me determine if it’s the gears chattering or the axles in the bronze side-frame bushings. Any suggestions as to a cure ???
Mark.
Are you sure it is the trucks chattering…every one of them…and not the pwm setting by the decoders? It seems highly unlikely that all the trucks are having “issues”.
Well, maybe I should elaborate … when I first bought the units, they ran very quiet. Over time I began to have intermittent contact problems that wheel cleaning and track cleaning were not curing. Upon dis-assembling the trucks, I found that there was a substantial amount of grease on the axle ends. I assumed that possibly this may be creating an insulation of sorts and proceeded to totally tear down each truck and remove what I thought to be excess lubricant from a manufacturer !!! Having gotten all the grease removed from the parts, I re-assembled everything and placed a couple drops of plastic compatable oil on the top gear and allowed it to run in.
Having everything all put back together ( yes, correctly ! ) it sounds like the gears / axles are chttering in their seats (?). It’s almost as if all that grease that was in there was tightening everything up and making it run quieter. I’m hesitant to do it, but should I just go ahead and pack the thing full of grease again ??? - doesn’t sound like a smart answer.
Is this how the manufacturers are now creating these stunningly quiet engines - by packing them full of grease so there is no possibility for vibration ???
Finally, to avoid rebuttals, all the engines in question were purchased brand spanking new - no one including myself got their greasy hands near them before my discovery.
Mark.
Mark, I sure wish someone who could help you more had responded by now because I am a bit out of my depth, especially with diesel models.
That said, if you have left no acceptable substitute for the grease that you removed, then yes you must go back and provide something. Many guys will tell you that you only need enough to coat every individual tooth lightly, not so much that it will quickly fly off due to its own mass when the gears spin up. And yes, grease, not an oil in the gears.
Could it be that the wipers are surrounded by either corrosion or a now-dirty lubricant that is meant to also transmit electricity? Maybe they are being denied the proper contact that they need to keep power from being intermittent. I don’t know what this conductive lube is called or even where to get it,…probably Walthers?
It is possible that all your gears, if they were manufactured as part of the same batch, are somehow defective, or are in some other unfathomable way not providing the function that they are designed and meant to do, but it seems highly unlikely to me. Still, we hear endless complaints about some P2K and Athearn gears, and they are in different models.
Mark,
I have a U33C with very little run time on it, and I bought it brand new about 8 years ago. I haven’t popped the trucks apart yet, but I don’t see any grease on the journals, just a brownish oil that tends to seep out when it’s in storage. The axles are clean. Is it possible that the oil thickened and/or attracted dirt from heavy use? The trucks on mine do seem to be overlubed.
I recommend Labelle 106 for the gears. That might quiet them down, unless there’s some sort of mesh problem.
Thanks for the response.
Electrical conductivity is not the issue now as all surfaces ( from my extensive cleaning job ) are now clean and shiny. There is no hesitation now at all … solved THAT problem !!! The Atlas engines transmit current from the axle tips to bronze bushing which in turn are attached to a heavy copper plate attached to the back-side of the plastic side-frame. A wire is attached to this strip to feed the motor.
I was wondering after the fact if the grease I discovered on the axle ends / bushings was in fact a di-electric grease and possibly SHOULD have been there as there was no evidence of the grease on the axle ends having migrated across the wheel faces (?). As of right now, the axle ends / bushings are clean / polished / dry. A dry axle turning in a loose tolerance bushing probably will create a harmonic vibration ( causing the chatter I’m experiencing ) and the grease will eliminate this ???
All of these engines have had minimal usage with the absolute most use being six hours total on any one engine.
Mark.
At this point, what have you to lose? Also, would you be able to run them stripped down to an extent so that you can watch the gears? You may be able to spot something, maybe that a spacer is required at this point to keep the gear axles from vibrating back and forth…dunno.
Sorry I can’t help any more.
-Crandell
That’s the frustrating part - they WERE nice and quiet BEFORE I tore them apart to clean out all that grease. Probably should have just left well enough alone, just wiped the axle tips clean and carry on. [banghead]
Mark.
Why don’t you run them upside-down with the gear covers removed to see if you can pinpoint the chatter? The axle bearings would have to be severely worn to cause any chatter, which would come from the gears overmeshing. That’s not going to happen with 6 hrs. of run time.
You took them all apart, and all are now noisy. So there are two possibilities, to my view…restore the lubricant, or you have inadvertently mis-assembled/reversed them…somehow. I can’t think of anything else, other than that they are sufficiently worn at this stage that removing the grease allowed the increased tolerances to be that much more apparent in the form of the chattering. You may need nylon shims or spacers to get the gears to mesh better. This would seem odd with so few hours, but you never know…
Is this the one that looks like an Athearn box with a bunch of spur gear lined up inside the case?
http://hoseeker.net/assemblyexplosionAtlas/Assembly%20Explosion%20Atlas%20U33C%2036C.jpg
Plastic sideframes with metal wheel wiper inserts behind the sideframes?
How far down did you tear them?
If it was my engine, I would take one truck all the way down and inspect each gear with a magnifier to see any marks or wear.
Clean and re-assemble the gearcases with oil on the shafts and grease on the gears.
The, I would make sure the wipers were seated into the sideframes properly, get some conductive lube (and I have used Gunslick Graphite in the past) into the metal holes in the wipers.
Before putting the sideframes onto the axle stubs, look at the tips and the inside/outside of the wheel for marks.
Is the wireholder in the correct place?
Not rubbing anything?
I would also look at the worm and shim installation to make sure it matches the diagram.
If the weights are not installed correctly, they could be rubbing on the shafts.