I bought this little MTH PS2 engine (MTH 20-3287-1 Light Mikado) and the Pittman motor is making an increasingly annoying noise.  It's almost like a shriek as you go over 5 MPH.  (It sounds like scraping a nail on slate). I have removed the shell and narrowed it down to the back of the motor.  I did check the front of the motor, thinking that the flywheel might be rubbing on the frame, Hall effect sensor, shell or wiring... but it is not.  Here's the best part.  This motor is NLA from MTH.  PERFECT.  Anyone have any suggestions before I dissect this little ghoul?    
 

 

TCA# 15-70824

Original Post

It is very surprising that a PIttman motor would make noise.   I have them in a bunch of locos and I have never had the motor be the problem, it has always been something else in the mechanism.

That said, could the screeching sound be a lack of lubricant on the motor bearings?     Would it be worth putting a drop of very fine oil on the shaft at each - perhaps Wahl hair clipper oil, or Labelle oil?    Maybe the factory worker screwed up and assembled the motor with no lubricant.     While some PIttmans have ball bearings, there are still many around that just have "oilite" bearings, sort of a porous bronze that I guess holds lubricant.    Some may be just plain bronze.

Would it be possible to disconnect the motor and see if the mech still makes noise?

Lubrication would be my guess too.  How many miles are on the Mikado?

 My table saw motor started squeaking and I narrowed it down to a motor bearing.  The operating manual talks about lubrication of various parts, but says nothing about the motor.  I stuck a camera under the motor to get a picture of the label plate so I could look for a replacement motor.  The motor label plate calls for no lube on the pulley side but once a year on the other side.  A little oil and the squeak is gone.

Bob

Measure the length. Lionel has 56mm and 61mm long Pittmans. They will work. The exact model number is not critical. I have used Lionel motors with PS2 upgrades.

They have oilite bearings. They are oiled by the bearing manufacturer not at the MTH factory.

Pete

You should be able to lubricate that bearing back to life. Pete is correct, it is an oilite bearing emulsified by the MFR. ......best to leave a small puddle of oil on the bearing surface, and allow it to soak in....if you can remove the motor, and stand it up on each end, gravity will do the work.....also, when you put a drop of oil on the shaft, if there’s any play in the lateral movement, go ahead and lightly rock it back and forth to work the oil in....use your favorite oil, this ain’t a science project....do the front and back since you’ll have it apart....flywheel is held in place with a set screw. Slight wiggling will walk it off once screw is loose....one trick I do for stubborn offenders, after oiling and allowing it to wick in, wipe a tiny bit of grease on the bearing surface...just a tiny smear, will help trap the oil in the bearing.......hope that helps......Pat

The Water Level Route.......You Can Sleep

The Pittman motors I've seen in MTH locos were not of the ball-bearing variety.  (Note there are ball bearings in the gearbox which absorb thrust loads from the worm gear.)  So it's entirely possible that the bearing could be dry, or even worn a little oversize and crying out for lubrication.

What's really good about MTH is that the worm gear isn't pressed on the motor.  Even the flywheel comes off easily with a tiny Allen screw.  So you just have to find another Pittman motor.  Try to match the first four numbers:  If the original loco had a 9432xxxx, you should replace it with a 9432 to ensure comparable performance.  Pretty sure that a 9433 or 9434 will be too long in a Mikado.

A 9412 would also work, but the '3' in the 3rd position indicates rare earth magnets which make the motor more powerful.  So a 9412 would give you similar size and RPM but less torque.

Pittmans are labeled with the nominal voltage of their windings.  It would be ok to substitute a 15.1 or even a 19.1-volt winding.  But I wouldn't use a motor wound for less than 12V (factory spec.)

My $.02.  Hopefully a drop of oil cures it, at least for a little while.

Creep, coast, and pull.  We're not talking about cold fusion here.

Ted S posted:

The Pittman motors I've seen in MTH locos were not of the ball-bearing variety.  (Note there are ball bearings in the gearbox which absorb thrust loads from the worm gear.)  So it's entirely possible that the bearing could be dry, or even worn a little oversize and crying out for lubrication.

What's really good about MTH is that the worm gear isn't pressed on the motor.  Even the flywheel comes off easily with a tiny Allen screw.  So you just have to find another Pittman motor.  Try to match the first four numbers:  If the original loco had a 9432xxxx, you should replace it with a 9432 to ensure comparable performance.  Pretty sure that a 9433 or 9434 will be too long in a Mikado.

A 9412 would also work, but the '3' in the 3rd position indicates rare earth magnets which make the motor more powerful.  So a 9412 would give you similar size and RPM but less torque.

Pittmans are labeled with the nominal voltage of their windings.  It would be ok to substitute a 15.1 or even a 19.1-volt winding.  But I wouldn't use a motor wound for less than 12V (factory spec.)

My $.02.  Hopefully a drop of oil cures it, at least for a little while.

Push come to shove Ted, the back side of the OP’s Pittman will accept either or bearing. The oillite bearing is retained by a spring washer. If the bearing is wallered out, it can be easily repaired with a new oilite bearing, or it can be substituted with a ball bearing insert and shimmed accordingly. The end cap will accept the insert. ( fixed a few this way) the nose end is a different story, the ones with oilite bearings, usually don’t have the swedged section on the shaft to press on the ball bearing insert....no harm, no foul having one of each.....aint like any of those MTH engines spin their motors to the moon.....😉.....Pat

The Water Level Route.......You Can Sleep

gunrunnerjohn posted:

Pat, where do you get the bearings for these?

From my drawer....😉..sorry buddy, I had to...seriously, the local robot club had a bag of them, and let me get a handful....they do that robot fight thing, they rebuild those Pittmans all the time.....apparently those motors don’t like being beat all to death......Ya need a couple? I can spare some.......Pat

The Water Level Route.......You Can Sleep

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