Looking for general advice on Kumata E3/6

[Sharky_McSharknose]

Pictures attached. That big wire sticking off of the E1A frame has a LED on the end. Told ya it was sloppy!

I noticed is that it's a pain to put the shell back on the A units. The fuel tank skirting gets in the way. The headlight housing on the E6A would need to be moved up a bit on the nose and a fillet added underneath to be more prototypical. Another headlight housing would be needed underneath to make it match the ACL's E6A. Don't worry, I'm not going to hack into these engines, I'm just thinking out loud.

[u18b]

Sharky,

Sounds like you have mixed bag.

The E3/6 may run above average.

The E1 is typical.   And wow- the light wiring is awful. I often us a modified light board out of a modern locomotive.  For example, I add DCC to an Atlas GP38.   Well, I keep all those old light boards.   The ends can be clipped off and jumper wires added to make them work.   And since they are flat, they can be made to sit right on top of the gearbox.

[u18b]

Wobbly shafts is a problem in these locos.

A SLIGHT bit of the wobble comes from the bearings themselves.  Not much, but a tiny bit.  The stock bearings are not exactly loose, but they could be a few angstroms tighter.  That may not sound like much, but a tiny difference becomes a bigger difference with a long shaft.

The bigger problem is often that the Zamac gearboxes don't hold the bearings tight enough.  Kumata knew this.  Because you will often see epoxie residue when they glued then in place.  That probably worked well when made.   But these locos are now 30 years old and the epoxie has long deteriorated- becoming crumbly.... which can then foul the gears.

If you disassemble the gearbox and get it off the locomotive and then reassemble it (so no truck and no motor to obstruct it), then you can see how much play is in the shaft.  I have had some where I could wiggle the shaft almost a millimeter or so-  that's pretty loose.

While not the best solution, I often replace the bearings entirely.  I found a typical Kato Delryn bearing can be modified to work.    The gearbox hole is round and the bearing is square.  So what I do is take a fresh Xacto #11 and trim the inner corners of the bearings.   I try- fit.... try some more.  Until the bearing fits snugly.   

This is not ideal since you have to keep the bearing square.  If twisted to the side slightly, it will add friction to the shaft.

But I have successfully done it many times.    There are other options.... but if you can't help someone repeat it because the parts are obscure then it's not helpful.  (for example, I LOVE the old Atlas RS-3 bearings... plastic housing with a ball bearing the self corrects it's own alignment..... but where are you going to find those?   The Kato bearings is a bit of a hack-job, but at least they are readily available.)

[u18b]

I moved, and I've only just unpacked the trains.

But when I can find everything, I'll take a photo to show you what I mean.

[Sharky_McSharknose]

Thank you for the advice. I will investigate the gearboxes on the E1s.

I know what you're talking about with the spherical worm gear bearings, and I know some of my locomotives have then, though I don't remember which ones at the moment.

I like the idea of using a discarded light board for mounting a headlight. I have plenty of the split boards from Atlas, Kato, and Life-Like locos I've converted to TCS CN/CN-GP decoders. The LED itself looks like the prototype's headlight when installed so I will reuse it when I get around to removing the rat's nest that's in there right now.

[Sharky_McSharknose]

I might as well make this my project thread.

I removed the E1B's motor and one of the worm gear towers. I don't see any evidence of epoxy deteriorating in the two halves and they are holding together. I'm not seeing any deflection in the end of the shaft when I rotate and tilt it manually. However, the worm gear is shifting back and forth between its bearings. It looks like I will need to add some thrust washers.

I tested the motor with a Kato power pack and alligator clips. The motor smoked something fierce on startup and I was seeing excessive arcing on the commutator when the power pack was cranked up. That might also account for the big speed difference between the E1A and E1B. It looked like there was a lot of carbon buildup on the commutator. I cleaned the commutator with some CRC 2-26 which fixed the arcing problem. I still think the E1s will need better motors swapped in if I plan to keep them.

[Sharky_McSharknose]

I took the E1A unit apart today. Before I did, I gave it another run around the test loop both with and without the shell installed. It sounded quieter than I remember at first (maybe the lube needed to work its way into all the nooks and crannies, or maybe I'm mis-remembering things?  ). However, I noticed arcing where the front motor wire tab is screwed to the gear tower.

After taking the front and rear trucks and gear towers off, I moved the worm gear shaft like I did with the E1B's parts. Same results - the halves feel tightly bound together and there's no deflection in the worm gear shaft but the worm gears are shifting back and forth between the bearings. I'd like to install thrust washers to prevent this from happening. How can I undo the epoxy holding the gear tower halves together, and what should I use to put them back together? Something like JB Weld?

The plastic collars on the insulated gear towers of the A and B unit all look good except for the one that touches the rear motor tab of the A unit. That one looks like it has fused to the motor tab. It may still be doing its job electrically but I'd like to replace it if possible. There was a clear piece of plastic under the A unit's front gear tower that wasn't present in the B unit. It has openings for the gears and the screws. Any ideas what it is for?

Finally, I think I'm going to replace the motors in the E1s. The B unit's motor is on its last legs- despite cleaning it the best I could, the commutator still looks like a sparkler at high RPMs and it has noticeable speed dips. I don't have any donor motors handy, so I'll either have to wait till the next train show in August or buy a pair of NOS Mashima motors to match what's in the E6s.