I've remotored several older Athearn Blue Box locomotives, using either Sagami or Mashima can motors, and dozens of brass steamers using Mashimas. For the Athearns, all with the older universal couplings, all that was required were shaft adapter bushings for the motors, from NWSL...
I added weight to all of those locomotives, and they were not only very smooth runners, but exceptionally good pullers (DC operation).
If the Genesis motor/drivetrain is a drop-in fit, it's a good solution, but there may be cheaper options.
Wayne
I believe that North West Short Line has all the parts you need for a BB conversion. Even kits??
Good point, LenS. After my first post, I wondered the same about the Genisis motor dimensions, and if they are actually a "drop in".
I've remotored my share of Athearns, too, but I have always used a newer version of what the excisting is.
To the OP, Athearn still has the ATH 84086 in stock. This motor might be a better option than the two motors you are looking at, for a BB loco.
Good eye opening post, LenS.
Mike.
EDIT: http://www.athearn.com/Search/Default.aspx?CatId=THCR&SearchTerm=ATH+84086
My You Tube
I've remotored many BB locomotives, only because I feel the newer motors run quieter and better. I use Athearn 84086 motors, new drive shafts and new worm gears. Makes a huge difference. Many replacement motors for BB are available on the dreaded EBay, both the old style and new style drivelines.
I wasn't aware that the newer Genesis motors were direct replacements for the older motors in BB frames. It was told to me that the dimensions were different, so I never tried them.
Good luck.
Len S
I have only remotored a couple Athearn Blue Boxers.
.
NWSL makes a good kit with one or two wide or narrow flywheels and universals included. It was ledd than $60.00 for the kit.
-Kevin
Living the dream.
I'm thinking the ATH G63842 is the one you want. The G63839 comes with the light board, which you don't need, as you are staying DC.
Even if you wanted to go DCC, the board that comes on the 63839 is pretty much useless, as it does not support light functions, except head light and reverse light, in 1.5 v. If you want to add LED's to these, with the board, you need to tap into the decoder harness, and attach resistors. It's just easier to hardwire a decoder with full light function.
EDIT: OOPS, along with what Mel posted, as I was typing. You'd have to get the "dog bone" style drive shafts, with the hex drive on the flywheel side, to make it fit.
Which Athearn Genesis motor would be a direct replacement in a Blue Box GP40-2? I want to leave it DC. I can't find the difference between 63842 and 63839.