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I was given a dual Pulmor motor Lionel F3 IC 8580. The engine appears to be in really good shape. Both motors also appeared to be in really good shape.

I ran the engine and heard what I can only describe as a horrific combination of screeching and grinding.

After greasing the worm gear, plastic drive gears and adding a drop or two of oil into the armature port at that the top of each motor, the screeching was no more. But what I did notice was the armature exhibited quite a bit of "float" while spinning (see video below. Sorry for the sideways video.....that was easiest way to record the spinning armature with the engine laying on its side). If you zoom the video you'll see the armature float much better.

I measured the amount of vertical play for each armature. The front motor armature moves vertically .8 mm. The rear motor armature moves .6 mm. Is this normal? I'm wondering since these motors are so clean looking; someone worked on them before and lost/left out a few parts?

This is my first foray into working with older Pulmor motors, so I'm hoping one of you could provide some insight.

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Pullout Motor Video
Last edited by Junior
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Hi Bill...if you're talking "gravity"; I'm embarrassed to say I didn't think of that. I was just focused on creating a video.

Hi WBC...  .01 inch/.254 mm is about 1/128 inch.  WOW! Parts are definitely missing. I will pull the motors apart to see what's missing.

I'm pretty sure thrust washers at the top are missing. I would think I should be able to see them above the commutator.

Here's a pic of the top of the motor with the brush housing pulled up.

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As we guessed....no thrust washers.

I took a look in my "Complete Service Manual for Lionel Trains" book (by K-Line) for that motor and it had the same picture you provided.

1619566787291287972617

But....neither shows thrust washers above the commutator. I'm beginning to think the problem might be below the armature where the bearings are?

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  • 20210427_162309
  • 1619566787291287972617

This motor style would not need thrust washers under the brush plate. Vertical play should be constrained by the E-clips above and below the bronze bushing. Possibly one or more washers are missing in that area.

It is also possible that you have lateral play, so that the rotating armature is contacting the stationary field. Try turning it with your fingers and see if it scrapes. This could happen if the bushing is worn, or bored oversize; or if the field is assembled slightly rotated with respect to the die cast motor base.

nickaix: I pulled apart one of the motors last night. I didn't notice any lateral play, but didn't specifically check for it either. I will check for that today.

GRJ: I have the Lionel Steel Switcher and seem to recall the instructions for that engine provide steps for adjusting that set screw (which I did do).

The F3 came with the original instructions. I'm guessing those will provide a positive indication whether the engine/motors should (not) have those set screws.

Thank you both for your thoughts on what else I should check.

The 2028-100 motor (used in F3s, GP7/9s, EP5s) has no set screw to adjust armature vertical play. If there is too much vertical play just add additional 671M-23 thrust washers either above or below the armature bushing to adjust it. MPC/LTI/LLC 2028-100 motors were assembled slightly more sloppy than their postwar counterparts. I've seen several locomotives with this motor from the 90's with extra thrust washers from the factory on either side of the thrust bearing (instead of the usual one on each side of the thrust bearing) to adjust the vertical play. Adding extra thrust washers is fine, it won't hurt anything.

Lou1985 & GRJ....

Checked the original Instruction sheet....

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No mention of a set screw at the top motor housing.  I already sent an email to my Parts Guy to confirm he has the Thrust washers, bearings and bushings etc. in stock.

In the meantime, I'll check the motor armature for lateral play.

Thank you so much guys! Your help will allow me to get this engine in tip-top shape in no time.

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nickaix: I checked for lateral movement on the armature. If there is any, I can't really tell. Also, there's no scrape marks on the armature itself.

Everyone: I was fiddling with the armature and the following question came to mind. If I add a thrust washer onto the bottom of the washer/bearing set (just above the worm gear); that will pull the armature down and create more space between the commutator and the brush plate. But that will also center the armature vertical in the field coil.

But if I put add a Thrust washer onto the washer/bearing set just beneath the armature windings that will raise the armature putting the commutator closer to the brush plate and put the armature slightly out of center with the field coil.

Any of you have thoughts on which is more suitable?

Last edited by Junior

This may be a dumb question, but what the heck . . .

Is the purpose of setting the vertical play to cause the brushes to have appropriate pressure  against the commutator?

If Yes, then should one have a new set of brushes in place when setting it?  If No, ignore me.

Brush springs get weaker due to heat.  If you run your engine hard, replacing them can be a good move; certainly cheap.

The very early postwar motors  (2333 etc) had brushes with a very high copper content  (as evidenced by their color).  Does anyone provide such a version today?  I am assuming they have better conductivity then the more common ones available  (could be wrong, of course).

Whining of a motor, for me , has always been a dry interface between the top of the armature and the brushplate (the bushing in the brushplate  and the armature shaft, to be clear).  Very distinctive sound.   Whistle tenders, too.

thanks!

John

Last edited by CPF3

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