How To: Fixing the "Whine" Kato C44-9W Mechanism

[atsf_arizona]

Hi, all, hope you can help me out with some of your expertise and advice. (I cross-posted this over on the Atlas Forum as well, btw).

I dis-assembled a N scale Kato C44-9W diesel split-frame mechanism in order to pull out the trucks and paint some details.

Upon careful re-assembly, the mechanism now whines when running at speed. On the workbench, I can hear and feel the split-frame mechanism + drivetrain have a very slight vibration when it is turning at speed. I've carefully tried to find places of mis-alignment, but so far, have not found the source.

1) How does one go about finding and solving the source of the very slight vibration?

2) Tools / tips to use? Is it possible to 'balance' the rotating drivetrain?

3) I'm wondering how the Kato assembly line (or Atlas, for that matter) is able to debug these mechanisms at assembly time and get them to run so smooth. If I knew that, maybe I could find what is the tolerance or the method of fine adjustment .... that gets disturbed whenever I dis-assemble and reassemble. I'm wondering if there are some tools, balancing scopes, or something that I could get and use.

It seems that the Kato split-frame mechanisms, whether they are the new models or the old 1994 era GP30s and GP35s, are silky smooth from the Kato factory.... but after disassemble and assemble, are consistently subject to whining (caused by slight vibration).

(P.S.: Please note that as this is a six-axle mechanism, it already has the universal joint in the drivetrain, so the Ron Bearden bearing block removal modification won't apply here).

I'll post pictures of the dis-assembled mechanism if anyone would like to see them for de-bug purposes.

Thx for any and all advice! Hopefully some great experience here to be shared with all?

Hopeful in San Mateo,

[oldrk]

May seem obvious.Did you try a little oil on the gears?

[dks2855]

My first thought would be to disassemble the entire unit, then reassemble it with just the motor. Power it up with test leads and see if it still vibrates. Then add one truck assembly with drivetrain and re-test. Swap out the other one and repeat. This may help to isolate and pinpoint the problem.

I've found that it's easy to over-tighten them and this can lead to very slight binding in the drivetrain. It might also be the universal parts might have been swapped or reversed; sometimes these fit so precisely that swapping or reversing them can also lead to very slight binding.

[AB&CRRone]

I took apart an Atlas GP-6 TT and when I reassembled it had a similar noise. Mine was caused because I didn't get the plastic bushings (right word?) at the end of one of the brass worms properly seated. Took it apart and reassmbled more carefully and the whine was gone. I don't have a C44-9W so not sure if this helps.

Ben

[Jeff B]

John,
I have several D9s with the whine you mention. My simple fix is too put a light coating of Labelle oil on the gears and rotating assemblies. Good luck.
Jeff

[tehachapifan]

I saw your post on the Atlas board where you confirmed with someone that you don't believe this is the classic "squeal" common th Kato and Atlas locos that is fixed via lubrication, but rather a different vibration of some type. Correct?

I have a really unscientific and shooting-from-the-hip theory that the classsic "squeal" is also as a result of very fine and rapid vibration, so the remedy could still be the same. This theory of mine says that the points where the flywheel shafts exit the motor and where the worm gear shafts go through the bearing blocks are potential source points of this noise/vibration when in need of lubrication. A tiny drop of lite oil in these areas have resolved the classic squeal several times for me before, although I've heard some people have fried their motor applying too much oil around the motor!

You may also want to try swapping the trucks from one end to the other and also play around with how tight you are screwing in the screws that hold the frame halves together. Try backing them off slightly. Also, as someone else mentioned somewhere, try repositioning the end bearing blocks (some develope what looks like a wear pattern on the gear side, which could be good or bad for vibration).

Russ

[atsf_arizona]

Guys, thx for the excellent comments and I'll give the bearing block oil a try - a light application won't hurt.

Furthermore, I'll investigate to see if I can isolate the cause of the vibration, or see what slight adjustments to alignment I can make, and what effect that has. I'd still love to know (or figure out) what Kato does at the factory to get the assembly quality they do!

For what it's worth, this Kato C44-9W mechanism was whisper-quiet before I dissassembled it.

I've disassembled and reassembled successfully, probably twenty split frame N scale diesel mechanisms over the past couple years - and consistently, I very much dislike dissassembling any Kato mechanism, as they seem so smooth before, and after re-assembly, these Katos - there always seems to be something disturbed in the dis-assembly / assembly process, and they are rarely as quiet as they were before. Ron Bearden's 4-axled diesel remove-the-inner-bearing-block method has been a godsend.

I'll keep everyone posted on the continuing investigation, and I appreciate your comments.

[atsf_arizona]

Thx for the thoughts, guys.

Short update after a debug session - dissassmbled the whole mechaism - the motor unit itself seems to be making the whine. Don't know why dissassembly would cause that. Will look further into this frustrating issue over the weekend.

I did oil the worm bearing blocks (the ones by the trucks) - didn't help, but it was worth a try. I am now investigating "how to balance a rotating mechanism" - I'll see what I can find on that topic on the internet.

[atsf_arizona]

Research update - via Internet searching, here's what I'mpurusing so far.

For what it's worth, some vibration analysis articles, somewhat interesting to read, albeit very techie.

I've observed and guessing so far that:

- there is a slight wobble in the flywheel as the motor rotates
- somehow a slight misalignment was introduced in dis-assembly
- I'm wondering how one could re-balance the flywheel, if possible

Anyone out there know anything about "vibration analysis" - and doing balancing of the small flywheels on the Kato part number #926030 motor?

My conjecture so far is that possibly I should have removed both screws of the split-frame mechanism at the same time. By doing them one at a time, possible something got ever so slightly bent? Anyway, we'll see what this continued research brings.

http://www.reliabilityweb.com/art07/machine_vibration_described.htm

- the above article describes how vibration is measured


http://www.reliabilityweb.com/articles/UNDERSTANDING_THE_BASICS_OF_BALANCING.pdf

- the above article describes how vibration is measured

URLs came from:
http://www.reliabilityweb.com/fa/vibration.htm

[atsf_arizona]

Research update - via Internet searching, here's what I'mpurusing so far.

For what it's worth, some vibration analysis articles, somewhat interesting to read, albeit very techie.

I've observed and guessing so far that:

- there is a slight wobble in the flywheel as the motor rotates
- this causes a vibration, that at speed, causes the split-frame itself to to vibrate and thus whine, I can feel the frame vibrate ever so slightly on the workbench at speed. My other (un-assembled thankfully!) whisper-quiet C44-9W frame does not vibrate at speed
- somehow a slight misalignment was introduced in dis-assembly
- I'm wondering how one could re-balance the flywheel, if possible

Anyone out there know anything about "vibration analysis" - and doing balancing of the small flywheels on the Kato part number #926030 motor?

My conjecture so far is that possibly I should have removed both screws of the split-frame mechanism at the same time. Anyway, we'll see what this continued research brings.

http://www.reliabilityweb.com/art07/machine_vibration_described.htm

- the above article describes how vibration is measured


http://www.reliabilityweb.com/articles/UNDERSTANDING_THE_BASICS_OF_BALANCING.pdf

- the above article describes how vibration is removed by balancing

URLs came from:
http://www.reliabilityweb.com/fa/vibration.htm

[Nelson B]

John, Did you try a drop of motor bearing lube were the shaft exits the frame?

You have to consider that if the problem was due to an unbalanced flywheel, the motor would have been just as loud before you first disassembled it. The only way you could have made a change to the balance would have been if you bent the motor shaft, and that will take some doing (like dropping it on a hard floor).

If the motor bearings (bushings) are dry, it will cause the shaft to chatter and induce both noise and vibration.

[Metro Red Line]

One of my Kato locos is making an intermittent whine as well...I attribute it to the warm weather; apparently the temperature has expanded some of the metal and plastic parts inside to where they rub against each other when they hadn't when the weather was colder.

[atsf_arizona]

Hi, all,

Hi, Nelson B, thx for your input. Yes, I tried your tip as well - no luck.

I think that in this particular case, somehow the motor/flywheel assembly is vibrating enough to case the infamous Kato split-frame "sounds like a turbine whine" noise problem.

I was very interested in your post over on http://www.therailwire.net , where your thread was posted showing a N scale factory balanced flywheel, on a *Bachmann* of all manufacturers! (a RF-16 Sharknose mechanism):

http://therailwire.net/smf/index.php?topic=12837.0

I include below here a re-post of a photo of the mechanism, where we can see the holes drilled to balance the mechanism, and Nelson, I noted your report that you removed the motor/flywheel assembly and ran it, and it was silent and vibration free:

http://www.trainboard.com/railimages/data/500/Sharknose_motor.JPG

From that thread, as well as other research, the bottom line conclusion has been
that no one knows any inexpensive, accessible way to accomplish the same
result ourselves. Hmmm.

Interesting, though, and wondering how Bachmann was able to measure and decide where
to drill the holes on the mechanism?

Continuing research. After all, what is this hobby for? sigh..... :-)

[sandro schaer]

i have around 300 kato engines and not a single one is noisy.

here are my suggestions :
- take the shell off
- tighten the screws holding the frame halfs together
- run the loco. still noisy ?
- unscrew the two screws by 1/4 turn
- run the loco again. still noisy ?
- unscrew the two screws by 1/4 turn again
- run the loco again. still noisy ?
- you might loosen the screws by 1/4 turn again.

don't loosen the screws too much cos otherwise the trucks will fall out


very often noises come from frames screwed together to tight.

[atsf_arizona]

All, I gave up trying to figure out why the original motor vibrates/whines at speed, ordered a new motor from Kato, should arrive later this week and I'll see what happens then.

Still don't know what happened in dissassembly / reassembly to cause the problem. Based on my personal experience with about six different 6 split frame Kato diesels, I think I will avoid disassembling Kato mechanisms unless I absolutely have to.

Sandro, thx for your tips, I'll give that a try as well, when I reassemble the mechanism.

[atsf_arizona]

Hi, all,

Just an update. I received from Kato the replacement motor, carefully installed it. The mechanism runs much quieter now, not as quiet as in the very beginning before disassembly, but quiet enough.

Of course, some issues still crop up......the loco's speed is not exactly the same anymore compared to the other Santa Fe Kato C44-9W that I have..... it's slower, although still close enough to MU. Go figure. As I am running analog DC, I do not have ability to adjust CV's DCC-style.

Good enough for now. Thx for all your tips and helping, everyone.

[Tony Burzio]

loco's speed...it's slower

Hmmm. Slower, that means friction. Have you tried disassembling the trucks and reassembling? Friction in the trucks can make the gear train buzz...

[Grey One]

I really enjoyed this thread. It's way beyond my ken. Still just a thought though a bit too late. You may want to take pictures of the various objects, enlarge and convert to gray scale or a "negative". I use this for method for seeing details. It may point out things that are out of alignment, bent or otherwise amiss.

[atsf_arizona]

Thx, Tony, for the thoughts.... I think in this case, it's a manufacturing tolerance variation in the speed at which the motor rotates. The replacement is a little slower, not enough to be a problem, but not exactly the same as the other loco. Originally, the two Kato C44-9Ws were almost exactly the same throughout the speed range. (I did go through a little tuning exercise already with new motor, did not want to bore you-all with the details). As the replacement Kato motor is from a manufacturing run potentially 6 years newer than the original motor, I can see how this variance might be.

All this is incredible, if I'd known I would have caused such self-inflicted headache, I'd just have used a fine brush and dry-brushed the truck gear towers carefully. That is what I did with the other C44-9W, obviously, and it works fine and took me 10 minutes to do. Geez.

Regardless, I continue to wonder - what is it that Kato (or Atlas) does at the factory to assure the quality consistency that they get? If I knew that, I'd certainly love to apply those techniques. New Kato six-axle locos certainly seem to run at consisently the same speed with older ones......

On that train of thought (no pun intended.....) I have heard and seen of Mitch's Precision Trains of Virginia - he does a superb job of tuning these kinds of Kato locos and others, to a incredibly good level. He's usually at Baltimore area Great Scale Shows, and he usually attends the N Scale Weekend in Bedford PA in August. I and others are universally impressed with the way his tuned engines ran when I saw them at two different train shows:

Mitchell R. Brown
14001-A Franklin Fox Drive
Centreville,Virginia 20121
Telephone 703-803-6761
e-mail precisiontrains@aol.com

I was thinking I should I should hire him and satisfy my curiosity.

Anyway, Tony, thx for taking the time to comment, if anything develops, I'll let all know.

[Dave B.]

Very interested by your tribulations and efforts to get rid of noise. I have two CN c44-9w. One runs very quietly the other screetches. After taking a close look and running the unit in my hand on one half of the frame, I realised that the motor and gear were fine. Also, it was not the meshing with the wheel assembly gears as it screamed without them. "Bearing Retainer" !! It seemed to me that it could be pushing the shaft and gear when the unit is assembled. I used a small flat screwdriver and pushed it in so as to take some of the spring out of the retainer. Voila! Has eliminated 90% of the noise plus the unit is smoother. Must look at so other units. Hope this helps you. Dave B.