New Motor for the USH USRA 0-8-0?

No, but I have remotored similar.  Pittman 8434 ball bearing silver graphite.  Actually, any Pittman numbered 8x3y.  The 3 is critical, the x is length, and the y is pin out style.  Attach with safety wire or small hose clamps, and couple to the gearbox with Toyota #0 rubber tube.

I dish the frame slightly, drill two #60 holes transversely and use an old chunk of inner tube as a cushion.

I do have one of these - I just never bothered to run it.

when sagami's were good a 3253 was real nice.

That loco has a good gearbox.    In my experience working with USH locos, any I have worked with have good gearboxes.    By that I mean it works well with gear reduction to use higher rpm motors and still run the loco at decent low speeds.     So any motor that is a "good" motor and fits will work.    I would avoid the cheap round motors with pressed steel frames often found in cheap toys and low end 3 rail products.    these are meant to look like can motors, but are not.

There is a Pittman motor that runs at lower speeds  and is quite torquey.  Does anybody know the number of THAT one?  -Rusty Rails-

this is the pittman I have used in many a US Hobbies locos...I have done this set up exactly as Bob has stated above. innertube under the motor, slightly dish the frame and Toyota rubber hose #0.....perfect results every time...the 9234 is very torquey in my opinion, have had very good luck with the USH gearboxes and pittman motor swaps....I will admit, I have done the 9234 in a 0-8-0 USH, its a tight fit....got to think about what you are doing....but its worth  the effort.

I too used the 9000 series motors exclusively when I started building in the late 1980s.  I did maybe ten locomotives - half Diesel and half steam - before discovering the smaller, higher RPM 8000 series.  Others wildly disagree with me, but I think the 8000s are better for O Scale.  You get good low end torque, much higher top speed, and for steam, lower drive shaft.  I think I have around 30 models with 8424 motors.  Happy!

bob2 posted:

I too used the 9000 series motors exclusively when I started building in the late 1980s.  I did maybe ten locomotives - half Diesel and half steam - before discovering the smaller, higher RPM 8000 series.  Others wildly disagree with me, but I think the 8000s are better for O Scale.  You get good low end torque, much higher top speed, and for steam, lower drive shaft.  I think I have around 30 models with 8424 motors.  Happy!

you are probably right Bob, I never used that motor, but others have told me about the 8XXX motors.....geez...look at the date on that 9234....that's the last time I ordered pittmans .......

Harmonyards and BOB2,

I was thinking of the Pittman 9233.  Same diameter, same magnet but a bit shorter.  I have this motor in a bunch of USH engines and they run very smoothly.  Not to be disagreeable, but are you sure that you squeezed a 9234 in the USH 0-8-0?

Regards,

Ed

I don't think that is disagreeable.  Maybe I shall take a look - the thing needs a new gearbox anyway.

For the record, the last digit is length.  All other factors equal, longer is more powerful.  The 9000 series are more powerful than the 8000, and if low speed power is what you want, the 9000 is better.  The 8000 is plenty powerful, and lots faster, so it gives me a wider range of control, and more opportunity to bury the drive shaft.

Ed, the 9234 will fit in that 0-8-0....I wish I had pics of that build, but I don't....I built that loco for a customer who lived in Northern Va. He modeled the central's yard in Harmon complete with an operating hump...this particular 0-8-0 was used as a trimmer engine that had to climb and descend the grade of the hump...so power was a must....to fit the 9234, I had to trim a tiny bit off the input shaft of the USH gearbox....just a tiny bit....use Bob's recommendations as your guide, he is on point....it really boils down to purpose.....how do you intend to use this loco?.....running a branch with local deliveries?.....use a 8000...dragging 15 cars up an incline cause your towerman is having a bad day....9000.....ENJOY and have fun....build it!

Either one has enough oomph to slip the drivers. Mine is at the airport - I will bring it home for a photo shoot.  I think I have a couple of different size motors.

Harmonyards and BOB2,

Thanks for your help.

Cheers,

Ed

Harmonyards,

The ashpan mounting tabs on the USH 0-8-0 interfere with the width of a Pittman 9000 series motor.  An 8000 series motor would be a better fit but maybe you know something I do not know.  I had this model in my shop a few years ago and did not want to modify the firebox mounts and refused to install a 9000 motor.  IMO, an 8000 series motor will provide plenty of power for an 0-8-0.

Joe

Joe, If memory serves me correct we did have to modify the ash pan mounts, and shorten the input shaft......an 8000 series is a great choice. At the time we did that Locomotive in 2001 or 02, the fella that owned it insisted on a "big motor" ......So we made it happen....I cant remember all the details, and I sure wish I had pics of that build. It turned out very nice.....but it was a very tight fit... you are quite correct...an 8000 would work just fine....no argument from me!

Let me see if I can post an iPad photo:

Well, that worked. 9433 - you can squeak it in if you cut the ash pan tabs.  Boiler is obviously cut for a high driveshaft, so that would be no problem.

Here is the 8224.  It is longer than the above dash 3 length, but it fits (if I cut the drive shaft on the back). 

It may take some time, but I will try the 8224 and a Mod 0.5 gearbox.  We'll see . . .

Put the Mod 0.5 in this AM.  This is a really tiny model, and probably needs something smaller than an 8224.  Next step is to dish out the frame to hold a can motor - it looks like a 3-length Pittman 9000 would be optimum with the USH gearbox.

I have never much cared for the USH or indeed any idler-gear setup.  That is a personal thing, mostly related to appearance and noise.

BOB2,

Thanks for the pictures.  

Do you think a NWSL 23:1 Mod 5 or 6 gearbox would make the 9233 or the 8224 fit better?  Does Pittman make a 8233 motor?

Ed

I don't think the 9000 series is a good fit at all.  Both series have 2, 3, and 4-lengths.  I could look it up, but I think the lengths are the same for an 8233 and a 9233.

The model is very light.  I am thinking "Cannon" at the moment, but if I find an 8x33 laying around, I will install that.  I could just fake it with an aluminum cylinder.  More later - I need to machine the frame tonight.

Re: Pittman 8000 vs. 9000: a long time ago an engineer from Pittman told me that brush motors really aren't designed to run continuously below about 800 RPM, below that too much of the input energy is converted to destructive heat.

The 8000 series can achieve about 8800 RPM in typical applications.  That gives an 11-to-1 speed range (say 4 to 44 scale mph.)  The 9000-series can only achieve about 6000 RPM in typical applications.  This gives a much more limited 7-to-1 speed range.  So you have to choose between great slow speed, or reasonable top speed.  Not a big deal on a switcher, but I agree with Bob that in a road steam loco with a decent gearbox (USH, NWSL) the 8000-series with rare earth magnets is a better choice.

Remember, gearing multiplies torque.  So an 8434 turning 800 RPM and geared at 25:1 to the wheels will outdo a 9433 turning 800 rpm geared at 16:1.  And if you add a good-sized flywheel to the motor shaft, the smaller motor turning faster will do a much better job at overcoming transient frictional events without lurching.

OEMs often use the larger motor with taller gearing.  IMO this is done to reduce complaints of noise and vibration.  If the motor is mounted in rubber, or with rubber grommets, the NVH can be eliminated.  I adhered a sheet of Dynaxorb (automotive speaker sound deadening) to the crown sheet of one brass loco, quieted it right down.  This is mostly a problem with brass.  There's a reason they don't make tubas out of die-cast metal ;-)

Good one! My patented safety wire mount admits to a rubber cushion.

Here is the finished product.  It runs!  The reverser yoke had to be cut, and the frame dished.  I can take it apart and show you the dished sections, if you decide to change gearboxes.  If you open the photo up you can see the extra cap screws holding the yoke halves in place.  I had put this off for a decade!  Thanks for spurring me into action!

bob2 posted:

Good one! My patented safety wire mount admits to a rubber cushion.

Here is the finished product.  It runs!  The reverser yoke had to be cut, and the frame dished.  I can take it apart and show you the dished sections, if you decide to change gearboxes.  If you open the photo up you can see the extra cap screws holding the yoke halves in place.  I had put this off for a decade!  Thanks for spurring me into action!

very nice work!

BOB2,

Very nice, indeed.  Thanks, Bob.

Regards,

Ed

Something nice has happened to this forum: the resolution of these photos is good enough to actually expand the detail.  That, and I can still post photos.  Not true on my favorite forum - they are full up.

I probably will pull that motor and scrounge around for an 8233 single shaft.  It will fit lots better.  Meantime I am slipping a "servo-Tek" generator in there, just because it is easy to swap out.  Who knows if that will work.  I may have a small Sagami . . .

BOB2,

Did the 8224 allow the back head to fit properly or was there a problem?

BTW, I called Pittman and they no longer produce the 8233 or any of the 8xx3.

Thanks,

Ed 

It is still double-shaft.  I was going to pull it out and return the model to display status.  But since you asked, I will try to see if it fit.  It is going to be very tight, so fore and aft placement will be critical.  Did you check for an 8222?

I set up my quartering jig while installing the new axle gear, but did the driver by eyeball.  After a 40 minute run-in, there is still a tiny hitch in the get-along.  I will fix that as well.  More later.

BOB2,

The 8222 is available but the continuous torque is 1.6 oz-in vs 2.6 oz-in for the 8224.  The lengths are 2.070" for the 8222 and 2.445" for the 8224.

Ed

Ed - good news - it fits.  Just did a test run.

My installation is on an angle, so I had to take a 1/8" piece out of the rear floorboard for a comfortable fit.

Might I assume you will be using the USH gearbox?  If so, you can mount it horizontally, and not cut a thing.  The secret is to put the front of the motor about 1/8" aft of the screw holes for the old forward mount.

I recommend a cradle.  I use leftover chunks of brass tube, but almost anything will do - PVC pipe, for instance.  When you attach it to the frame, leave a tiny bit of space for very small hose clamps or safety wire.  Adjust height of motor with strips of rubber.

I could not use a cradle - I cut the frame right up to the mid point of the rear axle to drop the motor down.  Caution is advised when making cuts like that - it can weaken the frame.  Seems to be plenty of frame left on this one.  I used an end mill, and cleaned up with a Dremel disc.

good luck.   Do not ask me why the photo got in the middle of a sentence.  Observe the absence of a gearbox above the drivers.

BOB2,

Clever engineering and excellent execution.  Thanks for following through with this project.  You have helped immensely.

Thank you, again.

Ed