GS-4 re-motor project update

[carlso]

Thanks Loren,

I appreciate your time to help. Yes the expansion link has been repaired, by me. I am not sure what was holding the expansion link onto the frame but whatever, it broke off and was gone. I used a #84 wire drill and drilled a hole as close to the original as I could and then pinned the link on with some PB wire in the top hole on the link, so it may not have the same "as built" characteristics. The as built link was attached about 1/2 way between the top and bottom hole but I can not see any effect on the hesitation. I was just tickled to make the repair as I do not see KATO repair parts for this beast.

Thanks for the explanation on the worm gear. Just shows how little I know, as I have been calling the worm, the worm gear. I wish I knew where I could find gears to fit, I would replace all of them. Not sure but it looks like 4 or 5 idlers in the gear tower plus the worm gear.

Thanks again for the input, much appreciated. I like to be a "hacksaw" when it comes to something like this and not give up.

Carl

[carlso]

Latest video. I think I shall say "good enough" and see what transpires. Thanks for all of the suggestions and comments................

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Thanks for looking.

Carl

[powersteamguy1790]

Nice work Carl.

[victor miranda]

that is yummy.

how are you going to mount the shell?

victor

[peteski]

Carl, the video is a bit choppy for me but it appears to run very smoothly.  However with that gear-head I would still expect a full driver rotation to take 30-40 seconds at it slowest sustainable speed.   That is one of the big things about this type of re-powering. You can simulate the loco starting *REALLY* slowly on your layout (just like a real loco would start). Without gear-head motor it is often difficult to smoothly and consistently achieve such slow speeds.

[mmagliaro]

Carl,
It is definitely better.  I count about 15 rpm.   I also would expect to get more like 3-4 rpm when
everything is really cherry in that mechanism.  But 15 is still pretty good.
With 80" drivers, that's  about 3.5 mph. 

I think it would be good to see what it does on the track before tinkering anymore.

But it already runs way slower than any of the GS-4's I've ever seen. 

[carlso]

Thanks to all for the comments.

Victor, I have milled the two top 1/2's of the KATO frame so that they will slip over the motor, that waya I still have the "normal" KATO mounting of the boiler shell.

I am going to do what you have suggested and have already re-mounted the decoder. I will test on the club layout soon. I now think that the gear noise I hear is from the worm/worm gear interface. I think the worm gear is so worn and extremely loose in the tower t be causing misalignment of the two. I will piddle with it. Heck I may decide that I need to see if NWSL has one that would work then again I may decide it is OK as is (????).

Carl

[strummer]

Thanks to all for the comments.
 I will test on the club layout soon.
Carl

Be sure to post a video when you do... Nice job.

Mark in Oregon

[peteski]

I now think that the gear noise I hear is from the worm/worm gear interface. I think the worm gear is so worn and extremely loose in the tower t be causing misalignment of the two. I will piddle with it. Heck I may decide that I need to see if NWSL has one that would work then again I may decide it is OK as is (????).

Carl

Carl, correct me if I'm wrong but aren't you using the original Kato GS-4 worm, bearings and worm gear?  If that is the case, and they are mounted as they were from the factory, there should not be any excessive play. Kato designed it with their usual precision.  Why is (or do you think is) the worm gear worn?   That should not happen to these locos unless they had many hundreds of hours or running time.

[carlso]

Peteski,

yes, this loco is running the "as built" KATO worm and worm gear. Why do I think the worm gear is worn ? Because I can see it and I can see the teeth are worn down and in fact they are worn down a little more on one side of the gear than the other. I can even see this with my two naked "plastic" eyes and when I put on my Optivisor I can see it better.  I do not think they are meshing properly and that is causing some noise. Not bad, but still there. And as I wrote before, the worm gear is extremely loose in the gear tower and it will move from a straight line to angle of approx 15 degrees. I know KATO made the running gear loosy goosy so it would run better on tight radii, but I don't think it would have been manufactured this way. This unit is from the very first run and has many hours of continuous running on home layout as well as N Trak layouts all over the country. It probably easily has 100 hours+ of operating time. Basically it is worn out and I may be wasting my time but being a hacksaw I will not give up.

Now, let me say that I do not remember if the worm had the plastic bearing on both ends of the shaft because I did not take a picture before removing the worm. I assumed that I lost one of them and placed two on when I reassembled the thing. Again, I assume two is correct? ? ? I do not have the exploded view  that came with the loco. Not sure how only one bearing would be correct.

If anybody has one of the exploded views that came with it would you be willing to jpeg me a copy? ?

Thanks for looking and I shall conquer!

Carl


Carl

[mmagliaro]

Carl,
I found a top-down shot of that mechanism from some other project on trainboard, and yes, that worm
has two bearings.

When you cut part of the frame away to mount the new motor, did you disassemble the whole thing, down to the frames,
taking out the drivers, gears, and all?  And then file etc, and clean it all up and reassemble the frames with the
idler gears inside?

Maybe when you put those frame halves back together, you didn't get something quite right with that idler.
Maybe the frames got a little bent, or perhaps... are there two very similar idlers inside?  Maybe you switched
positions?  I'm just thinking that maybe that's how that idler is wobbling between the frames.

Alternatively, if you did not take the frames apart, then there could be metal dust or chips down in there that
are causing trouble.

If that gear is wobbling 15 degrees, that sounds to me like it is simply too loose between the frame halves.
Either the frames got bent, or the gear is in the wrong spot, or maybe you just got a loosey goosey one.
You could take the frames apart and put some NWSL bronze thrust washers on either side of the idler to
keep it more centered.

[carlso]

Max,

I did NOT strip down the lower 1/2 frames that house the drivers, gears, etc.. I did not have to do any milling on that lower 1/2 of the chassis, only the top two 1/2's that had the motor encapsulated. Yes, obviously I removed the top 1/2 to do the milling. So I did not take the lower 1/2 apart and check anything else. The bronze washers are a good idea but that means I need to strip it down totally.

You know, I am attempting to become "more knowledgeable" regarding steamers and the best way to learn would be to have at it and totally strip it down. Would it be as easy as field stripping an M-1 rifle ? Yea sure it would be.

I  know that I am becoming a pest on here but if I decide "to start over" I'll document the findings. Perhaps there is some value for others to do so.

Carl

[peteski]

Carl, I just took apart my almost-new GS-4. Here is a photo of the gearing.

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As you can see the worm has 2 bearings which are tightly held by the chassis.

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This closeup shows the meshing between the worm and worm gear.  It is as-expected.  But if the worm bearing clip which snaps on the top of the chassis and which holds the worm bearings down was loose or installed improperly then the worm could ride up which would affect the meshing.  Of course severe tooth wear on the worm gear could also affect the meshing.

The gear axles are fairly short and they ride in cups molded in the frame.  Not my favorite design but it seems ot work ok.  This is almost new model (probably less than 3 hours of running time) and the gears do have quite a bit of sideways play. So this is normal for this model.  Even with that sideways gear play the model runs smoothly. I would not try to install any shims.

If and when you decide to strip your model I hope that we will learn what was causing the problem. Maybe as you said, the worm gear has worn teeth.

[mmagliaro]

Peteski:
GREAT PHOTOS!  THANK YOU!

Wow, those are nice gears.  And now... heh heh, we know that they are 27 tooth .25 module.

Very interesting, because I am pretty sure that all common Kato and Atlas diesels use 0.3 module gears.
Therefore, a diesel worm will not properly "drop in" to a Kato GS4.  It might work, but not very well.

Carl, do you have any idea if this excessive gear wear you are seeing was there before you tried running with
the replacement Kato diesel worm?  I have a bad feeling about this.   Putting the wrong module worm in there
may have worn out the gear teeth.

Oh... and Carl, you are certainly not in any way a "pest" about this!   This is wonderful.  You are doing hard work,
and we are all thinking and exploring, and learning   I can't think of a better way to spend my time.
(well, I can, but... )

[carlso]

 Peteski,

great pictures, thanks for the posting but more than that thanks for going that extra mile by tearing yours down. I personally can't thank you enough.

Max,

I did not notice worn gear teeth when I first pulled the GS4 worm, however I probably created this problem because I did place a KATO F-7 worm into the chassis and ran it on the bench for probably 5-10 minutes. I decided it did not run any better and pulled the F7 worm. I did notice worn teeth and as I stated earlier they are worn more on one side of the gear than the other. My bad! ! !

Now to continue the "how to screw up a loco for dummies" class, please help me understand the .25 module. Obviously I get the # of teeth but not the "module".  Is that the width of the tooth at the base, the width of the gap between the teeth, or the height of the tooth ?

Carl