GS-4 re-motor project update

[carlso]

I have been messing around and ignoring my GS4, maybe I was actually not sure of the results.  Here is a short video, made today, that I made after finishing the decoder wiring. The Zimo decoder is in the cab with only red/black leads to/from tender. I think it looks pretty smooth but would appreciate any comments from TRW. I will hold off installing the boiler shell, cab, and smoke box door. The decoder is a non sound unit.

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Thanks for looking and any comments yay or nay.

Carl

[peteski]

Um Carl, you did ask...

 I don't see anything very impressive.  Your step 1 speed is way too fast.  To me at step 1 the drivers should take several seconds for a single revolution.  That loco should be crawling.    Also on a test stand anything can be made to run well.    Running the model on a test track or on a layout will expose any possible pickup problems (I know there shouldn't be any electrical pickup problems with that loco).

You should be able to play with the decoder settings to get this loco to really crawl smoothly at step 1.  That is what geared motors and good decoders are good for.

[carlso]

Um Pete, I sure did, and thanks for the reply.

I do know what geared motors and a good decoder should do. What I failed to write was that this was without any tinkering with the decoder. I will use my JMRI and play with the speed table to get that crawl you are looking for and BTW, I agree with you. However, I am not sure I agree with you in regards to being able to make anything run well on a test stand.

Carl

[mmagliaro]

Carl,
The engine is not really on the rollers at all.  Only 1 driver is on the rollers,
and the rest are hanging between or riding between two rollers.   So I'd fix that and then retest.

Youtube video makes it hard to tell if the rotation is really smooth or not because sometimes the Youtube videos
themselves jerk around.   But it does look like there may be a hesitation in the motion.  With  a 4:1
gear motor, it really ought to be able to maintain very low speed (as in 1-2 mph or better) without
any hesitation.

My next suggestion is to test it without the decoder   Run it on DC and test it that way.
Before you start messing with speed steps, run it on DC and make sure the mechanism, gearing and motor are working
right.    It will be very hard to know what needs to be adjusted or where a problem is if you
try to diagnose this with a decoder in the mix.

[peteski]

However, I am not sure I agree with you in regards to being able to make anything run well on a test stand.

Carl

What I mean is that running on a test stand does not emulate real life conditions like dirty spots on the track or going through turnouts. Even a loco with a really crappy electrical pickup will run well on a test stand.  Of course if the mechanism itself is binding then that will show up on a test stand.

[nscaleSPF2]

It looks to me that the main side rod is bent, into sort of a "Z" shape.  This isn't going to help.  It should be straight.

[mmagliaro]

The siderod is jointed in sections.  There are separate rods from 1-2, 2-3, and 3-4, and with the 4 drivers not
being all supported level because the engine isn't on the rollers correctly, driver #3 (where #1 is the front)
is dropped below #2 and #4, so the side rods are simply flopped out of line.  But in practice, on uneven track,
it should still run okay like that.   Some of the drivers on this engine were designed to ride up and down
in their slots to accomodate uneven track.

The Maxon 1017 motor should easily be able to churn out enough power to move those wheels smoothly by
the time it hits 1.5 volts.   When I remotor a Trix K4 with a Maxon 13 x 20, if I can get it down to where it
will run on the track at 0.8 to 0.9 volt, I know it's getting good.

I still say bypass the decoder and start running it on low DC voltages.  That will show you
if you have the worm gear mesh right and if there is a quartering bind.

[peteski]

The bottom line (at lest to me) is that the reason to install a coreless motor with a gear head is to greatly reduce speed and greatly increase the available torque.  With this type of a motor installed the engine should be able to crawl at a scale speed 0.1 miles/hr or less, even with a heavy train behind it.

Carl's video shows it running at probably 20 scale miles/hr even at speed step 1 on the DCC decoder. That to me is totally missing the point for this install.  The video is a bit choppy but I am certain that viewed in-person it runs perfectly smooth. GS-4 is already a very smooth mechanism and the geared coreless motor will even make it run better.  But it is just way too fast at its slowest speed.

Max is correct - if this engine was without a decoder then it should start running at a fraction of a volt. That is assuming that Carl's analog throttle actually goes that low.  If it is an old rheostat-based throttle then it will not be able to provide such a low voltage and the engine will take off fast, even at minimum throttle.

[nscaleSPF2]

The siderod is jointed in sections.  There are separate rods from 1-2, 2-3, and 3-4, and with the 4 drivers not
being all supported level because the engine isn't on the rollers correctly, driver #3 (where #1 is the front)
is dropped below #2 and #4, so the side rods are simply flopped out of line.

I see it now, Max.  It looks like Carl needs to get all the drivers at the same height before we can make any judgements.

[carlso]

Thanks for all of the comments/suggestions. I have adjusted the test stand so all 4 drivers are on the rollers and I have removed the decoder. My analog dc power pack is an MRC Tech3 model 9000 and I will make another short vid after dinner.

After watching the vid I made yesterday, I noticed something did not appear correct in the #4 driver. Yes I saw the strange looking  short rod between #3 & #4 driver and I could not get it to straighten out. I pulled the retainer plate and found that the left side #4 axle bearing slipped out and was lodged against the back of the driver. The axle had no lateral movement, so it must have been causing a bind. I placed the two bearings back in correctly, I think and perhaps I will see a smooth movement now. Why would it act up that way, after a special fix had been applied to it? Perhaps the #4 driver not being level ? ? ?


Carl

[mmagliaro]

Thanks for all of the comments/suggestions. I have adjusted the test stand so all 4 drivers are on the rollers and I have removed the decoder. My analog dc power pack is an MRC Tech3 model 9000 and I will make another short vid after dinner.

After watching the vid I made yesterday, I noticed something did not appear correct in the #4 driver. Yes I saw the strange looking  short rod between #3 & #4 driver and I could not get it to straighten out. I pulled the retainer plate and found that the left side #4 axle bearing slipped out and was lodged against the back of the driver. The axle had no lateral movement, so it must have been causing a bind. I placed the two bearings back in correctly, I think and perhaps I will see a smooth movement now. Why would it act up that way, after a special fix had been applied to it? Perhaps the #4 driver not being level ? ? ?


Carl

This engine has the new drivers with the small bearings in it, right?  And #4 has one of my U-shaped
channel thingies in there, I assume?   That bearing should not pop out of place with that U in it.  But then,
it is very fussy and easy to not get it in right when you slip the cover plate back on.   Now that you are
sure the bearing is in right, keep an eye on it.   If it keeps popping out, then it looks like I need to work on that
"U" thing some more.

Woe betide those new bearings and drivers.  Honestly, knowing what I now know about those bearings,
if I had a GS4, I would buy a set of drivers and put them in a drawer "just in case", and keep using the old bearings
and drivers unless I have an axle tube failure. 

[carlso]

Max,

you are correct in all of your assumptions. The #4 driver has not slipped again, however. I find them interesting, your comments regarding the "new" drivers and bearings. I am convinced that all the hesitation in this video is caused by a very weak set up as far as KATO's running chassis. I just hope that the FEF is not going to develop similar problems. At any rate here is a combination of 2 videos doing all that you and others suggested. I appreciate all comments.

Carl

[Loren Perry]

The drivers need to be re-quartered. Instead of concentrating on the rod crankpins when the rods are in the down position, look closely at the counterweights at the top. You'll see a noticeable misalignment between axles 2 and 3. This may be causing rod binding resulting in the hesitation. Make sure the counterweights are as close to the same angle as possible - it's easier to see minor misalignments using them rather than the crankpins.

Also, there is a very slight vertical movement on Driver Axle No. 1. This may oir may not be a source of binding, but it's worth looking into.

[victor miranda]

Hi Carlso

the whole video it looks and sounds like a gear problem to me.

.... like the worm is floating?

it ran better with a ball and cup

If you can... add a dogbone?

victor

[carlso]

 This is for Loren Perry.
You stated that there is a misalignment between drivers 2 & 3. So that I am on the same sheet of music you are saying, as I do, that #1 driver is at the front of the engine. You stated a slight vertical movement in the #1 driver axle. I did not notice much there but the second one bounces way too much. I think.

I really need to talk to someone to understand the quartering on this one geared set of drivers.

carl