Questions regarding Lionel Pulmor motors

The reason for controlling the clearance in the thrust bearings is to keep the commutator from hitting the under side of the brush holder and to avoid impact loading the thrust bearings. And on early motors, to keep the balls from falling out.

There is no change in the strength of steel due to heat until above about 1100 degrees F.  Unlikely the brush springs run that hot.

Lionel used three different brushes in the post war era. They had carbon brushes, which are black and fairly light; they had copper graphite brush, which is black with a copper cast to them and are heavier; and they used a copper coated brush, which are a copper color, but the copper wears off the contact surface, which is then black.  New brushes are only available in carbon. NOS of the other two types can be found, but are getting rare. Brushes need to have significant resistance to control the current flow when the brush shorts across the commutator slots.

Hi David....I believe your post just answered my question regarding the vertical positioning of the armature/commutator vs. the motor's brush plate.

Sounds like I should add the extra Thrust washer(s) directly above the worm gear. This will pull the armature down, centering the armature in the field coil and providing more space between the commutator and the brush plate.

Hmm. I might be confused. Is the motor still making the sound that I hear in the video you posted, or did the lube you added fix that? I suggested lateral play as a possibility based on the sound, but maybe I misunderstood your post.

Hi Nickaix - Yes....and that sound is WAY better than the combination screeching-grinding I heard initially before lubricating it! 🤯

During the lubrication process is when I noticed the amount of vertical movement of the armature.

I didn't see any evidence of the armature scraping on the field coil.

FYI....I ordered a complete set of Thrust washers and all bearings including the sleeve bearing.

@Junior posted:

Hi Pete....

Yeah....I'm thinking the same thing. I think I'm gonna order 8 of the Thrust washers and 4 of the Thrust bearings (just in case they fall apart). Worst case is I'll have extras for my parts inventory .

"just in case they fall apart"

My recommendation would be to double your numbers of how many to get.  Here's my reasoning:

1. They're relatively cheap
   
   
2. They won't spoil or go bad in your parts drawer
   
   
3. You might someday purchase an engine with the same issue
   
   
4. During reassembly, when one squirts out your grease-covered fingers and flies in a graceful arc to some location that's completely inaccessible ... or completely invisible ... or both, your family won't have to hear those special words sometimes heard in the train room. 

Don't ask me how I know...

Steven J. Serenska

Steven....so poetically put....I LOL'd.....only because we can ALL related.....I know I can!

Ok, if you still have the sound, then I still think you have contact between the stationary field and the rotating armature. That is just the sound I would expect with that. You should not have that sound. The motor should be virtually silent. When you check for contact you have to remember that the armature is going to try its hardest to contact the stationary field in some manner. The motor works because magnetic fields are fighting with each other: things are not going to stay in alignment unless constrained. When you check for contact, try to push the armature as far our of alignment as possible, rotating with your fingers, and see if you can't find a contact point. It need not be a large area, perhaps just a burr somewhere, or a corner. Looking closely at this photo, I see a suspicious shine on the top corner of the armature segment. Looking even closer, I see faint abrasions, not yet through the paint, on its leading edge.

@Junior posted:

It may be that reducing the vertical play is enough to fix this, since that will also reduce the lateral deviation slightly (imagine the tilted armature shaft as the hypotenuse of a triangle). If it still persists, then I would be looking for an oversized bearing, or else out-of-alignment plates in the stationary field. Some file work might fix the latter problem. Or a hammer (carefully, of course!).

Nickaix....Thanks for all the great symptoms to check for....great stuff!

I will definitely check for all those and see what I find. Parts are on order and should arrive some time next week.

I probably won't post anything until next week. Out-of-Towners are arriving today for the weekend. My Wife LOVES to entertain so... you know.....happy Wife, happy Life! 😁

@nickaix....

The replacement motor parts arrived today. I already disassembled one of the motors and checked for armature "wiggle" with the existing bushing. Yep....there's quite a bit of wiggle.

I slipped a new bushing onto the armature shaft and tried the wiggle test...no wiggle that I can tell.

My question to you (or anyone else following this endeavor ) is; is the armature bushing just a friction fit or is it pressed into the motor housing? I'm hoping a little light "tapping" will free the current bushing from the motor housing.

@Junior

I have not yet needed to replace this particular bearing, but I know that the bearing / sleeve in the similarly-made horizontal motor used on the berkshire chassis is pressed in. Not with a great deal of force. If it were me, I would approach it with a length of wooden dowel and a small hammer.

Maybe someone who has replaced these will chime in, though.

Thanks Nick....I'll give it a whirl and see what happens. Future posts will be forth coming.

@nickaix, et al .....

The new bearings are in both motors. Bearing replacement went pretty smooth....but ran into one issue.

Neither of the armature shafts would slide all the way through one of the new bearings. The other armature shaft/bearing fit like a glove.

I measured both armature shafts and they measured 3/16 inch.

Needing something of substance to hold onto, I pressed the troublesome bearing into the motor housing, held my breath and drilled out the problematic bearing on my drill press. The bearing slid right onto the armature slicker then snot! Phew!

Bottom line; both motors hum like new....and for open frame motors run very well.

Here's a quick video of the final results....

Thank you all for your help!

A happy ending ... wonderful!

And congrats on that beautiful IC set!