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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?    
 

 

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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.

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 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.

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

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

Upon disassembly, the motor looked fine.  However, the self centering rear armature load bearing was dry as a bone and showed signs of heat stress and hysterics.  Oil impregnated my patootie!  I gave the little Pittman a full service internally.  It's my specialty.    No further squawking from this unit.

Last edited by Volphin

Talked to Charlie Pittman Jr. on the phone one Saturday decades ago.  He said any motor that has a side load should be ordered with ball bearings.  Lionel and MTH apparently didn't want to add the extra two bucks to their products.

If you ever replace a Pittman, always specify rare earth magnets (a 2 or 3 in the third slot), silver graphite brushes, and ball bearings.  The 9x34 comes stock with all that if you ask.  Not sure they still sell onesies and twosies direct, but when they did, they were half the price of elsewhere.

As mentioned elsewhere, I started out with 9000 series motors, but in the end would only use 8000 series.  I would order a box of 30.

Last edited by bob2
bob2 posted:

Talked to Charlie Pittman Jr. on the phone one Saturday decades ago.  He said any motor that has a side load should be ordered with ball bearings.  Lionel and MTH apparently didn't want to add the extra two bucks to their products.

If you ever replace a Pittman, always specify rare earth magnets (a 2 or 3 in the third slot), silver graphite brushes, and ball bearings.  The 9x34 comes stock with all that if you ask.  Not sure they still sell onesies and twosies direct, but when they did, they were half the price of elsewhere.

As mentioned elsewhere, I started out with 9000 series motors, but in the end would only use 8000 series.  I would order a box of 30.

Bob, they don’t sell onesies twosies anymore....I tried...I was able to buy some service parts from them....that’s about it...I’m afraid they’ve priced themselves right out of our market...I too, remember talking with Charlie Jr. directly and placing orders right with him....he was always interested in what I was building, and always had suggestions and a lot of knowledge....

one thing of note, common MTH Pittman motor 9434j434, is not a ball bearing motor, it’s an oilite bearing motor....it doesn’t come stock with ball bearings....I have 9433’s with 12V windings in a plethora of flavors, some of my 9433’s have ball bearings, some have oilite bushings....you have to decipher the entire part no. to distinguish all options, 9433F686 is a oilite bushing motor, while 9433L382 is a rare earth ball bearing motor....

I’d like to know the full number of the 8000 series motor you said is the go to motor...if you say it’s good, I’d like to find some and try them..... thanks!.......Pat

Last edited by harmonyards

No, I was told that the numbers after the 8434 were customer specific.  They do identify ball vs. oillite, etc., but only for that customer.  When you buy used or from a dealer you need to look.  Silver graphite is not really necessary - the regular brushes are good for 800 hours, which is a very long time for a model train.

Volphin posted:

Alright gents, after 2-3 hours of runtime, this little motor is noisy once again.  I used some light oil on the shaft and bearing.  I'm about to disassemble and relube with a wheel bearing grease.  I will silence this loco one way or another.  Any other ideas?

What’s the number on that Pittman? .....if memory serves me correct, it should be 9434J434......if you can’t get that motor to shut up, and you can pull it, send it to me,.....worse case scenario I’ll put a ball bearing end on it...I’m guessing from your other replies you’ve actually pulled the cover off and had a look around?....on the other side of the copper disc that retains the oilite bearing, there’s also a white cotton wiper that needs to be soaked in oil as well.....it’s hard to get oil in there, but it can be done.....forgot to mention that earlier....but I guess we thought you had this thing licked....clearly that motor wants to put up a fight....😡......Pat

@Peter B posted:

Can someone please provide photos showing where you can lubricate a flywheel motor?

What’s the item # you’re working on?...some times you can stick a pin oiler between the flywheel and the motor and get some oil on the shaft that way, and sometimes you have to physically pull it apart to properly lube one....all depends on what you’re working on......some react well to external lube, others that remain stubborn have to be pulled apart to get oil to soak in.....a good buddy of mine chased a squeaking Pittman in an Unshrouded MTH J for days until he finally pulled it apart and lubed it that way...

Pat

I just did this to my noisy Pittman. I ended up pulling the end of it off, saturating the cloth around the bushing with car differential oil per Pat’s recommendation, and then squirting oil on the bushing itself whenever I would walk by it. I took a q-tip and cleans off any access after doing this for a day or so and then reassembled it. I never removed the motor from the engine, pulled it apart in place. Before this, it would make noisy fairy quickly. After, it’s been running for 8-10 hours a day for the past week with no noise.

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