Best Of *Science* of solving N scale diesel mechanism drivetrain vibration noise?

[u18b]

You know it's funny Pete.  I haven't looked at that chassis in a long time, even though I have a couple.

Back in the day, I always assumed that was a port for easy lubing.
But of course it is open at the top.

It never occurred to me that it might be for viewing the mesh.

Good catch.

[peteski]

You know it's funny Pete.  I haven't looked at that chassis in a long time, even though I have a couple.

Back in the day, I always assumed that was a port for easy lubing.
But of course it is open at the top.

It never occurred to me that it might be for viewing the mesh.

Good catch.

I also never associated that hole with checking the mesh - I only thought about it after seeing what you did on your model.  I guess we really don't know what the true purpose of those holes is (because I don't think they really have a need to check the mesh at the factory).

[atsf_arizona]

I also never associated that hole with checking the mesh - I only thought about it after seeing what you did on your model.  I guess we really don't know what the true purpose of those holes is (because I don't think they really have a need to check the mesh at the factory).

Peteski, thx for the photos, that's interesting.  I have to go look at my Atlas/Kato SD9's mechanisms and see if they are there.

 (Pure conjecture): Perhaps the Kato engineers put the hole there to make sure these particular production mass-produced models actually had the correct gear mesh coming off the assembly line.   i.e.  in order assure Kato quality, maybe they wanted to easily quality-check and measure the production output's  gear/worm tolerances.     

But certainly, no hole = no way to measure or quickly inspect the gear mesh.  "If you can't measure it, you can't improve it". 

All, any other "tips" / "techniques" / "experiences" / "noise reduction war stories" you may want to bless us with? 

------------------------------------

This thread starts to remind me of other great locomotive mechanism tuning threads that I've seen, like this classic, superb Max Magliaro Railwire.net thread regarding "Concor/Kato/LifeLike Hudson tender 6-wheel truck (electrical pickup) upgrade" from April 2015.  This is a modification that I have to implement on my ConCor GS-4's to fix exactly what this Magliaro thread is about:

https://www.therailwire.net/forum/index.php?topic=35828.0



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I'm sure there are other loco tuning threads around that you all may have seen.  I humbly offer the following:

How to replace BLI/PCM wheelsets (and fix electrical pickup problems caused by traction tire):
http://www.pbase.com/atsf_arizona/bli_n_pa1_wheelset_replace&page=all

How to remove shell (and then install Unimate short-shank couplers) on Kato F's, E's, PA's:
http://www.pbase.com/atsf_arizona/kato_n_scale_unimate_install

The "trick" of removing the Atlas U25B shell:
http://www.pbase.com/atsf_arizona/n_scale_shell_removal_tips

The "tricks" of removing the LifeLike SD7/9 shell:
http://www.pbase.com/atsf_arizona/lifelike_n_sd7_shell_removal__renumbering   

The above was based on Andre Kritzinger's tuning articles:
Removing shell on LifeLike SD7/9's:  http://mysite.mweb.co.za/residents/grela/lifesd7-sd9.html
Fixing power pickup on LifeLike SD7/9's:  http://mysite.mweb.co.za/residents/grela/lifesd7truck.html


Know of others related to N scale loco mechanism tuning that are worthy to share here?   

I'm sure there's many internet threads the rest of us never heard of, that you could point out to us. 

---------------

This has been a great thread on tuning N scale locomotive mechanisms. 

Thank You All, for your participation. 

[Steveruger45]

I just quietened down a noisy kato gp35 using an adaptation of Ron Beardens's technique.  As the worm shafts on this loco are a little short I left the inner bearing block in but drilled out the hole for the worm shaft to give the needed clearance.  Works great. 

[u18b]

Hmmmm.

I can see how this would work.

The big hole acts as though the bearing is not there at all.  It allows the shaft to move a few microns.

But..... the bearing is still there and so it acts to retain the worm.  So this solves the issue that I bring up that adjusting the hex nut on the end is less critical.

You still have the extra friction from the inner bearing being there in the first place, but I can see that noise would go down.

The only caution that comes to my mind is that drilling into the bearing to make the shaft hole bigger may leave plastic burrs that would be counter productive since the worm edge rides on this.  I would make sure it is smooth.

[strummer]

This is a fascinating thread.

One might wonder if any of this could apply to the "old standby" in Z scale, the MTL F7? It can be made to run well, but is notoriously noisy...

Mark in Oregon

[Steveruger45]

The hole I drilled into the bearing block is big by comparison to the worm shaft diameter by easily 1.5 to 2 times.  The hole should be cleaned/de-burred too as needed.  I just ran the drill through forward and backward a number of times to achieve this.
Now the inner bearing block just acts to restrict inward movement of the worm shaft toward the motor while giving the needed flex without friction of Ron Beardens technique and solved the short worm shaft issue too.
I am not familiar with Z scale loco's but this should work, as long as all things being equal.

[NorsemanJack]

(bumping an old but VERY useful thread)

Thanks John for starting this thread a while ago and linking to it in a recent thread.  I've read all of the posts and appreciate everybody's efforts.

I have a new situation to offer, that I feel is relevant.  I recently purchased two brand new Kato E8 mechanisms that I believe were produced in 1993 and not ever ran.  Perhaps not surprisingly, they ran like clockwork straight out of the box.  I put them both through my baselining routine, and found that they ran at 61 scale MPH and 67 scale MPH at 5.0 volts (averaging forwards/backwards, both clockwise and counterclockwise around a 35 foot Unitrack loop with triple-cleaned - vacuum, alcohol wipe, Aztec track cleaning car - track.  59 SMPH to 74 SMPH is the full range I have observed over 22 such Kato mechanisms, most of them either brand new or recent production.

Next, I disassembled both of them to install brand new Kato trucks (purchased as new parts from Kato).  On one of them, I removed the motor/flywheel/universals/worms.  The other I only removed the worm covers and didn't disturb the mechanism.  For those unfamiliar with these mechanisms, they are of Kato's latest configuration that uses a one piece frame instead of the older split frame configuration.

Surprisingly, upon reassembly and test running, both were making more noise.  Probably the "coffee grinder noise."  Initially, the unit that had no mechanism disassembly seemed to be slightly louder.  Not really bad, but noticably louder than the units had been making with the original 25 year old trucks.  We've eliminated a lot of variables here.  For the mechanism that was not disassembled, the ONLY variables are the worm/truck interface and the truck gears themselves.  "Break in" is not an issue, because the orignial trucks had never been ran (I bought these from a well known N scaler/supplier who had bought two undec units for the shells and never ran the mechanisms).

The only thing I can think of is that Kato applies some type of lubricant to the worm at the factory that is not applied to the replacement trucks.  I just ordered some LaBelle 102 to test this theory and will let you all know of the results.  Am I missing any other possible explanation?

[u18b]

I also had thought that this unique thread should have been a best of thread- especially since the info is not from one person, but from many sources:  thus it is a great example of the heart of what we want and hope for on Railwire as a community.

Also... this thread captures some work done on the old Atlas thread..... which is now shut down and gone.


Jack.....  on your E8s.   It sounds like an alignment problem somewhere.  I don't think mere lube present or not present would make that much of a difference.

[NorsemanJack]

Jack.....  on your E8s.   It sounds like an alignment problem somewhere.  I don't think mere lube present or not present would make that much of a difference.

You may wish to reread my post.  If the one unit was quiet before truck swap, and the mechanism was in no way disturbed, how could an alignment problem suddenly appear?  Are you familiar with these one piece Kato frame designs (I'm pretty certain that you are)?  If all such symptoms were alignment related this thread might have better answered John's original questions.  Based upon my reread of the entire thread, I don't think anything conclusive has been determined for suddenly louder units in the absence of broken truck tabs or misassembly.  The vast majority of the other cases have, to date, no known verdict that I have seen.

Not so sure we can just automatically rule out total lack of lubrication on a new truck as a root cause, or at least the major cause.  If that gear and the original worm are suddenly experiencing increased friction, it most certainly could manifest itself as increased noise.  In a Kato unit like this, the only real "slop" is the intentional loseness in the worm/truck interface; which allows for the whole Kato "shock absorber" configuration to work.  I thought I had a unique situation to share, as I had brand new 25 year old units and brand new replacement parts that were obtained directly as a spare part (i.e. not removed from another unit).  We really don't have too many variables in this very unique before/after comparison.

[u18b]

Hi Jack.
Of course I read your thread.  Not sure why you think I may not have.  And yes..... I have a little experience disassembling Kato locos 

We may be using different terms.   When you say mechanism, I'm guessing you mean "drive line".

Because when you lift off the worm covers in order to get to those tabs that hold the trucks on.
Install new trucks.
and then replace the worm covers......

I'm not sure how you can not be touching or "doing anything with the mechanism."

Or to use your words....
"For the mechanism that was not disassembled, the ONLY variables are the worm/truck interface and the truck gears themselves....."

If you removed worm covers, pulled trucks, reinstalled trucks..... I'm only saying the trucks themselves are not the only variables.
But that's just my guess based on the sound you described.

While you completely disassembled the drive line in one, but not the other......

I was merely suggesting that maybe "something moved"- hence a slight alignment issue.

I still don't think that lube present or not present on new trucks would do what you've described.... but of course I might be wrong.

Looking forward to your report when you get some grease to add to the trucks.

[NorsemanJack]

Hi Jack.
Of course I read your thread.  Not sure why you think I may not have.  And yes..... I have a little experience disassembling Kato locos 

We may be using different terms.   When you say mechanism, I'm guessing you mean "drive line".

Because when you lift off the worm covers in order to get to those tabs that hold the trucks on.
Install new trucks.
and then replace the worm covers......

I'm not sure how you can not be touching or "doing anything with the mechanism."

Or to use your words....
"For the mechanism that was not disassembled, the ONLY variables are the worm/truck interface and the truck gears themselves....."

If you removed worm covers, pulled trucks, reinstalled trucks..... I'm only saying the trucks themselves are not the only variables.
But that's just my guess based on the sound you described.

While you completely disassembled the drive line in one, but not the other......

I was merely suggesting that maybe "something moved"- hence a slight alignment issue.

I still don't think that lube present or not present on new trucks would do what you've described.... but of course I might be wrong.

Looking forward to your report when you get some grease to add to the trucks.

You're right Ron.  Technically, by removing the worm covers, I did possibly affect the mechanism.  That said, I just can't believe that things would be that "touchy."  I was careful not to move the bearing blocks, worm, etc.  As you know, those worm covers only have plastic tabs that restrict upward movement of the bearing blocks during operation.  They are an imprecise part, but you never know.....  Maybe snapping them off and back on added some looseness that wasn't there before.  That's why we have this thread.  We know that multiple locomotives have had multiple root causes for noise.  That's why there have been multiple approaches to improvement.  Those locomotives did seem a bit quieter the next day without doing anything to them.  If that plastic has a "memory," maybe it recovered to return to the factory state?  I generally don't disassemble any locomotive unless I have to, and then only to the extent necessary.

Also, just to clarify, I ordered some LaBelle 102 gear lubricant.  I believe that is more of a medium viscosity oil than a "grease." 

[u18b]

I agree the drive train is pretty stable. 

Here is something that occurred to me in you odd situation.

1. Why did you change the trucks.  E8s are inherently quiet.  Sorry if I missed the reason.

2. Are you sure you replaced them with the correct trucks.

I know Kato went to a more shock absorber design.
I also know that one change is the contact strips up top are longer.
But are the trucks the same or different?
For example, if the pick up shoes on the new trucks are longer, then too much pressure would be placed on the trucks.

I don't have my computer to look up the parts.  Too hard on my phone.

[NorsemanJack]

I agree the drive train is pretty stable. 

Here is something that occurred to me in you odd situation.

1. Why did you change the trucks.  E8s are inherently quiet.  Sorry if I missed the reason.

2. Are you sure you replaced them with the correct trucks.

I needed silver trucks instead of black.  The replacement silver trucks are straight from KATOUSA.  They are the correct part.

[Boilerman]

Depending on the type of drive shafts that are used I know if there are u-joints on these small locos they must be in perfect alignment with each other from one truck to the other or there will be a noisy vibration emitted from the drive train that will be even louder when the body is back on.