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Repowering old brass

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  • Member since
    January 2009
  • 4,496 posts
Posted by RR_Mel on Wednesday, February 5, 2020 4:29 PM

I received the two Mabuchi FK-280SA-14200 motors yesterday and did a rough test.  The eBay listing says 6-15 volt .075amps no load 12300RPM.  At 12 volts it measures 10000RPM .0815amps no load.
 
I installed it in an Athearn Blue Box GP9 as DC only, I don’t intend to run 4 axle diesels in DCC mode on my layout.
 
I checked the Athearn motor after removing it and the RPM was very close to the Mabuchi.  The Athearn runs 12000RPM no load .2280amps at 12 volts.
 
Earlier I built a Mel Dynamometer using a Mabuchi SF266 with a shunt load.  I haven’t attempted to calibrate it but it does let me compare motors.
 
The Mabuchi FK-280 has considerable more power than the Athearn motor at less current.  The Mabuchi puts out 3.8 watts at 12 volts 600ma and the Athearn does 2.1 watts at 12 volts 1.2amps.
 
 
 
I would recommend the Mabuchi FK-280SA-14200 as a very good replacement for the Athearn Blue Box motors, slightly less RPM more power at less current.
 
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
 
 
  • Member since
    February 2010
  • From: Indiana
  • 140 posts
Posted by mikeGTW on Thursday, February 6, 2020 2:04 PM

Mel  looks good to me   I ordered a few of the 280 motors 

question  I know you use the nwsl 489-6    but I contacted NWSL and he recommended 491-6  2mm-2.4mm  with a drive shaft   but I'm wondering  if the 2.4mm might not be a tight fit on the worm  they are 3/32 or 2.3mm

so what you think 

  • Member since
    January 2009
  • 4,496 posts
Posted by RR_Mel on Thursday, February 6, 2020 2:37 PM

I only stock the NWSL 489-6 (2mm).  I drill them out with a #43 drill bit (2.26mm) the Athearn worm has a 2.3mm shaft.  With the #43 drill bit the universal cup is still a press fit.
 
I normally use a very small dob of super glue as a lube to slip the cup on the worm shaft.
 
 
EDIT:
 
Make sure the shaft doesn’t go in the cup past the bottom of the cup or it will interfere with the ball joint.
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    January 2009
  • 4,496 posts
Posted by RR_Mel on Thursday, February 6, 2020 5:52 PM

This is with the Athearn flywheels sleeved with 3mm K&S Brass tubing.  It becomes a drop in replacement.
 
 
 
Both are the same length so the original Athearn drive lines will work.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
 
  • Member since
    February 2010
  • From: Indiana
  • 140 posts
Posted by mikeGTW on Friday, February 7, 2020 2:34 PM

Mel  I ordered two of each the 489-6 and 491-6  so I can see what I can do  

I'm sure both will work just which one is "easier"

Also ordered 10 of those 280SA motors  from what you did they look very promising

I have a few of the old Mantua steamers   though about using one of the SF266 motors but needs major surjury on them  still might try it

Thanks Mike

  • Member since
    February 2010
  • From: Indiana
  • 140 posts
Posted by mikeGTW on Friday, February 14, 2020 9:36 AM
Mel I ended up ordering the 492-6 it is 2mm to 2mm but it has a 1 1/2 inch long drive shaft with it also the cups are roughly twice the size as the ones in the 489-6 kit far easier to hold on to and drill with the #43 drill to fit on the athearn worm The 491-6 works but the 2.4 mm cup is not a press fit on the worm still waiting for my motors to get here
  • Member since
    January 2009
  • 4,496 posts
Posted by RR_Mel on Friday, February 14, 2020 9:45 AM

The larger cup is probably better, I’ve broken a few of the smaller ball assemblies over the years because of the higher powered motors.
 
Just yesterday I was rewiring a Rivarossi Cab Forward with a Faulhaber 2224RS motor and stalled the driver wheels and snapped a ball joint.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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