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Generator bearing question

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Sarastro

Sarastro

Yoda
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OK, here I am again with a strange question.

My generator (60 Bugeye, stock) started making noise today, so I pulled it and checked out the bearings. Front seemed OK but the rear bearing surprised me--it was kinda dry and starting to wear. According to the shop manual, it should be a "porous bronze bearing," which I take to mean a sintered bronze bearing, like I've seen many times before in other places. However, the generator (which was rebuilt at one point, I think) had a simple brass sleeve to support the armature--no porosity that I could see.

It seems to me that the rebuilder probably just installed a brass sleeve, not appreciating the difference between the porous bearing and a piece of brass. Or, am I missing something? Maybe the bearing is different from my expectations.

Now, according to the manual, the lubricant reservoir should be filled with grease. However, even if it were a sintered bronze bearing, I have a hard time seeing how grease would find its way through the pores--oil, I can see, but grease? Seems unlikely. If you used oil, though, it might leak onto the commutator and brush surfaces. All in all, it seems hard to figure out how this bearing gets lubricated, with no excess that might leak onto the commutator.

So, how is this thing supposed to work?

Thanks in advance for any insight you can provide.
 
SA: The commutator end "bearing" should indeed be a porous bronze bushing. Commonly referred to as an "Oilite" bushing or bearing.
And, according to all my manuals, the required lubrication is a few drops of oil every 6000 miles, using essentially the same oil as the engine.
Prior to installing a new one, it should be submerged it oil for 24 hours before installation, to insure it is properly lubricated. I keep all of mine stored in a sealed jar of oil.
Jeff
 
Thanks for the response. I see that VB stocks the bearings, so maybe I'll just buy a new one and replace it to be safe. I also found that one of my manuals says to use oil in the reservoir, the other grease. I think I'll go with the oil.
 
Should be a peice of felt and a spring in that reservoir. Oil is the ticket. The spring pushes the felt onto the bearing.
 
Yes, the spring and felt are in place, and I can't see any porosity, but (in my limited experience, at least) these bronze, oil-impregnated bearings have a certain grainy look. This one looks like an ordinary slug of brass. But, maybe this one should look like that. I dunno.

I think I'll replace it anyway. It's worn, and they're cheap.
 
Go for it, good deal.
 
At the risk of flogging a dead horse--I did a little research on these sintered/porous bearings. It seems that it's quite easy to machine them incorrectly, so the pores on the surface get closed up. Then they just look like...<<*fanfare*>>...an ordinary piece of brass!

I'm beginning to suspect that this happened to mine--it was made by some cheapo rebuilder who didn't know what he, she, or it was doing. I suppose it doesn't matter, as long as I replace it with a good one. But I'm still puzzled. Not a good feeling, but one I've learned to live with when necessary.
 
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