Squealing Kato - fixed but need to understand

[MK]

I bought my first loco after a hiatus of a few years.  It is a Kato C44-9W, DC, used, from an estate sale.  From the looks of everything it seems to have low run time.  I have a bunch of Katos that I bought over the years and they run like Swiss watches as everyone knows.

But this one is an odd one.  Put it on the tracks and a loud squealing.  Not all the time, at certain speeds therefore at certain RPMs.  There seems to be two bands of speed where this happens.  OK, no biggie, it was probably sitting on the shelves and just needed some lube.  Removed the trucks and squealing still happens so not the trucks.  Took it apart and everything looks extremely clean...too clean.    Weird thing is that with the half frame removed and clipping on some power leads, the loco is quiet!  So it's not the motor - phew!

Since I have it opened, might as well lube it a touch.  Added a TINY drop of oil on both motor bearings and both sides of worm screw bearing block on all 4 blocks.  Put the half frame back on and WTH?  Still squealing but about a 10% reduction.  Still around the same speed bands.  So it wasn't dried out lube.  Process of elimination is taking more and more things off the list!

Just by chance I was fiddling with the bearing springs - for the lack of terminology.  It's the spring on one side of the frame that has two prongs that when the two halves are assembled they press against the pair of worm screw bearing blocks.  There's one on each end.  I noticed that when I press on them or fiddle with them, the noise is reduced or eliminated or the squealing shifts to different speed bands.  Hmmmmm!

I was thinking the springs were pressing too hard on the blocks since with one half of the frame removed and thus no pressure on the blocks, there was no noise.  I decided to push back a little on the 4 prongs to reduced the pressure on the blocks.  The squealing was GREATLY reduced but still there.  So I opened her up again and pushed the prongs back just a touch more.  Bingo!  No noise, no squealing, at any speed bands, forward and reverse.

I'm happy to have resolved it but I'm not sure I understand as with Kato's reputation of quality, did I just happened to get a lemon?  I know every loco is different but never in a million years would I have thought that I had to do this to a Kato!  Certainly I never did this for my other half dozen ones, even a similar C44-9W.  Maybe a little lube and that's it.  Or has things changed since I exited the hobby 5-6 years ago (though I don't think what I got is the latest run)?  Is it just as simple as bearing blocks too tight?

Can anyone explain?  Ron Bearden?  He was the king of loco noise reduction and the understanding of it the last time I was in the hobby.    Hope he is still around.

[tehachapifan]

Bearing blocks not orientated correctly, perhaps? Although I have not measured them, it is my belief that they are not square on many locos even though they appear to be so when you look at them from the sides with the holes (it's the inner surfaces that I believe are not the same dimensions, not the outer flanges). Even when I've set them up to go in in the proper orientation, I've had them roll 90 degrees on me by the time everything is pressed back in-place. I have noticed that, if the orientation is wrong, the worm will appear slightly out of alignment. I even had one loco where the frame halves would not tighten enough to keep the trucks in until I flipped the bearing blocks 90 degrees. The fact that many/most/all(?) of these bearing blocks have a smooth inner surface on two sides and a louvered-looking surface on the other two sort of backs up the theory that the dimensions are perhaps not equal. I wish I could say for sure which of these surfaces goes against what, but it's been a while since I messed with this (if they're even the same loco to loco).

[dougnelson]

I have the same squealing problem with one or more Kato E8s.  Can you post a photo of springs you are talking about?

[SP-Wolf]

I have the same squealing problem with one or more Kato E8s.  Can you post a photo of springs you are talking about?

What I found on an E8/9 of mine was the coupling on the motor shaft had a crack. I used some CAA glue -- no more squeal. Just something else to look at. Not saying this is your issue. Throwing out, my experience.

Wolf

[peteski]

We recently had a lengthy thread on analyzing and fixing various noises in our models. It is in the message archives.

Edit: this is the thread. While it starts off about vibration and growling I seem to recall that later on squealing was also covered.

In general squealing is usually emanating from the fastest rotating parts of the model. That is either the motor shaft/bearings or worm shafts/bearings (since they all spin at the same (fastest) in the entire mechanism.  Lubrication (using light oil) is usually the cure.  But I suppose that misaligned worm bearing blocks might cause that kind of noise. I usually bend those springy fingers out to apply  more pressure to the bearing blocks.  There really isn't some specific recommended pressure that I know of.

[u18b]

I second Pete.  "Squealing" I'd always a bearing some where (or some other moving part like some truck pick ups I some locos).

I always lube everything. 
If the noise does not go away, I start removing worms shaft trying to isolate the sound.  Usually, it's the motor.

Never run a squealing loco more than a few seconds.  You risk damage to the bearings.

[MK]

Bearing blocks not orientated correctly, perhaps? Although I have not measured them, it is my belief that they are not square on many locos even though they appear to be so when you look at them from the sides with the holes (it's the inner surfaces that I believe are not the same dimensions, not the outer flanges). Even when I've set them up to go in in the proper orientation, I've had them roll 90 degrees on me by the time everything is pressed back in-place. I have noticed that, if the orientation is wrong, the worm will appear slightly out of alignment. I even had one loco where the frame halves would not tighten enough to keep the trucks in until I flipped the bearing blocks 90 degrees. The fact that many/most/all(?) of these bearing blocks have a smooth inner surface on two sides and a louvered-looking surface on the other two sort of backs up the theory that the dimensions are perhaps not equal. I wish I could say for sure which of these surfaces goes against what, but it's been a while since I messed with this (if they're even the same loco to loco).

Ah, yes the bearing block orientation but I was aware of that from my lessons learned years ago when I started my foray into N scale decoderization.  It isn't the case this time as now I always note their orientation each time I open up a loco.  Also, this time, all the running parts remained intact on one half of the frame.  I was able to oil the parts without removing anything.

In this case, the smooth sides of the bearing block were left/right while the sides with the notch (Kato has two notches per side in this model) were top/bottom.

I never mic'd the blocks but I suspect they are slightly not square too.

[peteski]

It is fixed but you want root cause. So the question is: have you oiled the motor and worm shafts?  Yes, I know you think that futzing around with the springy fingers which retain the work bearing blocks fixed the problem.

Is the problem repeatable?  If you readjust the springy fingers, does the noise return, or is it now gone, no matter what you do? Also are you sure the noise you describe is a squeal (usually high pitch)?  Not a growl maybe?

[MK]

I have the same squealing problem with one or more Kato E8s.  Can you post a photo of springs you are talking about?

I'm going to borrow a random picture from Spookshow's website.

http://www.spookshow.net/loco/katoes44.html

In the naked picture, there two gold colored rectangle pieces to the left and right of the flywheels.  That's the spring I'm talking about.  Once you open up the loco, on the back side of these rectangles you'll see two prongs that stick out and they fit right into the grooves on the bearing blacks, holding them on.  You can see a little bit of this without disassembling the loco by looking top down around the worm gear area.  These springs are just clipped on to the frames.  They are only on one half of the frames.  The other side doesn't have them.

What I did, by chance, was to reduce the pressure on the bearing blocks by pressing the prongs back manually.  I figured, squealing with frames together but silent with frames apart.  (And I already ruled out the trucks, the motor and the lack of lubrication.)

All the diesels that I have opened from Atlas and Kato have these bearing block springs.  I'm just surprised that I had to do this to a Kato!

[MK]

It is fixed but you want root cause. So the question is: have you oiled the motor and worm shafts?  Yes, I know you think that futzing around with the springy fingers which retain the work bearing blocks fixed the problem.

Is the problem repeatable?  If you readjust the springy fingers, does the noise return, or is it now gone, no matter what you do? Also are you sure the noise you describe is a squeal (usually high pitch)?  Not a growl maybe?

Part of my original post:

Since I have it opened, might as well lube it a touch.  Added a TINY drop of oil on both motor bearings and both sides of worm screw bearing block on all 4 blocks.  Put the half frame back on and WTH?  Still squealing but about a 10% reduction.  Still around the same speed bands.  So it wasn't dried out lube.

Yes, it's repeatable if I pull the prongs back out slightly to increase the pressure.

Oh it's definitely not growling and definitely squealing...like a frightened pig!

[MK]

I second Pete.  "Squealing" I'd always a bearing some where (or some other moving part like some truck pick ups I some locos).

I always lube everything. 
If the noise does not go away, I start removing worms shaft trying to isolate the sound.  Usually, it's the motor.

Never run a squealing loco more than a few seconds.  You risk damage to the bearings.

Mr. Bearden you are still around!!!  The days of the Atlas forums. 

In my case I know it wasn't the motor as with the frames apart I hooked up a power supply directly to the motor leads and varied the voltage from 0-11 volts.  Super silent.  No squealing and the drive train was still attached (dog bone, universal, worm gear on bearing blocks on both ends).

[peteski]

Part of my original post:

Since I have it opened, might as well lube it a touch.  Added a TINY drop of oil on both motor bearings and both sides of worm screw bearing block on all 4 blocks.  Put the half frame back on and WTH?  Still squealing but about a 10% reduction.  Still around the same speed bands.  So it wasn't dried out lube.

Yes, it's repeatable if I pull the prongs back out slightly to increase the pressure.

Oh it's definitely not growling and definitely squealing...like a frightened pig!

I didn't re-read your post carefully enough. 

What does the model sound like when you put the squealing bare chassis on the track (with the trucks and the fuel tank removed)? Basically put the chassis directly on the track so each half contacts each track and then run it at various speeds. Is the squeal still there?

Also is it possible that the chassis got slightly bent somehow (maybe the loco was dropped)?

[MK]

I didn't re-read your post carefully enough. 

What does the model sound like when you put the squealing bare chassis on the track (with the trucks and the fuel tank removed)? Basically put the chassis directly on the track so each half contacts each track and then run it at various speeds. Is the squeal still there?

Also is it possible that the chassis got slightly bent somehow (maybe the loco was dropped)?

Don't worry Pete.  We all read too fast as there's so much to catch up on!

Bare chassis on track has the same squealing.  Identical with the fully assembled loco out of the box.  Also at the same speed bands when the squealing occurs.

As for a bent frame, possible but I doubt it.  Possible as I got this from an estate sale so I have no idea of it's history.  I doubt it as I don't see any deformity anywhere on the frame from a drop or hard hit.  The loco, from the shell to the frame to the inner parts look pristine.  I guess one way to tell is to strip the frame completely and lay the two halves on a glass table.  But....there is no way I'm going to jeopardize the quietness at this time. 

[peteski]

But....there is no way I'm going to jeopardize the quietness at this time. 

Well then, the "I need to understand" part of your post will not get fulfilled.  I'm pretty sure that what you did is not a fix but simply a workaround for the problem. 

[MK]

I understand the part of not being fulfilled.  But I don't understand your conclusion of a work around and not a fix.  It fixed the squealing just like as if a drop of oil might have fixed it or a bearing block adjustment.  It wasn't a kludge.  No duct tape was used.  It was simply taking some pressure off the blocks.  Why would you need that I don't know.  That's the missing part.

And if I were to strip the frame and place it on a glass table, and if nothing was bent, that would still get us nowhere.  And if it was I don't have another to compare to see if that was the norm for this particular model.  Maybe all of them were manufactured this way for this model?

I am pretty sure the frame is not bent from dropping but maybe from the factory?