brushes

[cwburfle]

IMHO, the replacement coil type brush springs that are sold today are often too long, and exert too much pressure on the brushes. It the original springs are in good shape, I often clean & reuse them. Otherwise, new springs are a must, and they often need trimming.

Excessive spring tension can actually make an engine run poorly, just as too little tension can.

[Bubba]

Thanks Bf i checked to see if the springs where going to coil bind and put to much pressure on the commutator and all seems well im going to give it a shot and run this thing. Again thanks for the info.Bub

[bfskinner]

Bubba,

I hate to speculate on this forum, but all I have are guesses on this one. The brushes that Lionel used on postwar locomotives seemed to be composed largely of copper. Pressed up against the commutator they made fairly good electrical contact, but their hardness often caused the commutator face to wear.

The only brushes that I have been able to find lately appear to be largely graphite and seem to be softer than the originals. These may well be better with regard to wear-and-tear on the commutator; but, other things being equal, seem to require about 2 volts more throttle to obtain the same results. Perhaps the longer springs are supposed to put a bit more pressure on the brushes to compensate for the change in materials.

In my experience a brush that is really too long will jam up in the brush well; that is, be compressed to the point where no further compression is possible. That's clearly not good.

As long as the brush-and-spring combination remains "springy" in the well you are probably all right. About the worst thing that can happen is that the brush itself will wear down a bit sooner. I'd try them.

No guarantees on this advice, however. I have been unable to find any "authority" or source for this opinion. If you are not happy, you might provide the dimensions of the old and new springs and see whether anyone else has better information. Good luck.

[phillyreading]

Could be the old brushes are shorter from years of wear.  I will venture to say the new brushes and springs should help the 671 very much.

I have used springs from pens on one occasion when I lost the original spring.

Lee F.

[Bubba]

I just recieved my brushes for my 671 the springs on them are longer than the originals is this a problem ?  or have the old ones just lost there tension. thanks Bub