Large Scale Central

1:29 Challenger Kitbash

Modeling
#21

The work continues… As noted before I received a motor from Rocky for the Yellowstone. It came with a different hex coupling than the other two motors I have on the bench. This new one has a coupling with a longer round section on the motor end of the hex section. I needed to replace a motor in the Mikado block being used on the Yellowstone as it ran twice as fast as the motor in the Mallett. This new motor can not be used to replace either of the other two as it won’t allow the transmission assy. to slip into the brick. here’s the new motor coupling:

and the old:

the brass coupler has an open end so coupler can be pulled off with a puller. New style is blind , no access to the shaft. An email was zipped to Rocky looking for info on the loco this motor came out of. Rocky reported the motor with the black coupler is from a new Pacific. The other motor/coupler is from a Mallett. I called Aristo and was emphatically told that they had made no changes , that the motor/couplers were the same from the Mallet/Mikado/New Pacific. The evidence at hand tells a different story. Received several tidbits from folks at LSC, MLS and Aristo forums. Suggestions included trying heat, cutting back the hex section until the shaft was exposed and then use a gear puller and pushing the coupler farther on the shaft to get the needed clearance. Another option I toyed with in my head was removing it and turning down the offending added cylindrical length so the transmission seats properly. Doing so using the motor means death to the motor with all the swarf being sucked into the motor. I could tape it all closed and drive the shaft with my small lathe and turn it down without removing it. There is insufficient room on the shaft of the newest motor (black Coupler) to move it far enough to allow the transmission to slip into the brick when the motor and tranny are coupled. Tried heat on the brass coupler and it came off after a short application of a heavy duty soldering iron. The new coupler wouldn’t budge. Started to cut on the end of the coupler but I couldn’t find the durn gear puller so figured that would just be a waste of time! Wrapped the motor in tape all over and chucked the long end of the hex coupler in the Unimat threw a tailstock on the other and turned down the offending portion. Made sure I cut enough so it wasn’t putting pressure on the tranny as Leonard warned about. Thing fits in the block like it should now so will test it out in the morning as I am done in for this evening. Attached is a pic of the modified coupler.

Thanks for all the assistance guys! Helps to work thru things with more minds on the job! Andre’

#22

Andre this looks like the making of a great looking trains never had the guts to do that yet but my time is near

#23

Thought I had this brick problem licked… Turns out a couple of the gear boxes in this Mikado block weren’t quite right. Too much noise and the motor heated up too much. The Mallett motor ran cool so I knew there was a problem.

I pulled apart the gear boxes and found a couple bearings that were rough. This occurred as I was also working on two very early SD45s. They were howling and I had spun a few plastic coupler hex drives and stripped two worms in their gear boxes.

Using all ten I was able to put together 4 gear boxes. Put them in and the Mikado block sounded fine. Ran OK too until I put the cover on. Then the motor starts running hot.

After several evenings of diagnosis, notice I didn’t say I was good at it, I discovered the last gear box was jamming against the top cover. The small outer raised ring around the flywheel hex coupler access wedged against the cover. Once corrected the cover fit better. Still ran too warm tho.

Started fiddling with the gear boxes’ placement in the brick. Discovered the gear boxes are not all exactly the same size and neither are the recesses for them in the block. Finally found spots for each that allowed them all to have a bit of forward and aft movement within the block. I needed to turn back the collar on the motor hex drive just a bit more to ensure the first gearbox had the same amount of needed free play.

Buttoned it all up, ran the assembly for over an hour on the bench. Cool as the Mallett!

Leonard had warned me of this I think but I read it as only the flywheel shafts needed free play. It wasn’t until I ran into the motor overheating problem that I got everything checked out.

If you are disassembling the block make sure you replace the gearboxes in their original spots. I assume the factory does the same “fitting” of the gearboxes to the block as I discovered was needed. You can probably mix them up as long as each has sufficient free play fore and aft. It appears from the work I did that they need to be able to move a distance about equal in depth to the small outer ridge around the flywheel hex access.

Andre’

#24

Andre ,
A lot of people would have given up long ago . Your persistence will be rewarded with something you can be proud of , I am sure .
Well done , sir .

Mike