Balanced Rotor and Spring Grease
 

I had a PM about balancing the distributor rotor, but the thread I found also has a picture of greasing the Model A spring, so I included that in the title.

To balance the rotor, I've tried a couple of ways, but removing the excess Bakelite and adding a couple screws is the easiest I think. I used my Dremel to remove the excess Bakelite from the circle, then used the Dremel to grind a couple holes for the two screws and nuts. It was basically just guess work, but the balance turned out great.

I used the same balancer that I used for the fans. You can also just use a couple of thin metal pieces to let the shaft roll on, such as a pair of razor blades. The small ball bearings I use have such low rolling friction that they work fine. If I spin the ball bearings against the wire wheel, that will limber them up for even less friction. I'd bet you could even rest the shaft on an ice cube to do the balancing. That should be low friction.

https://www.fordbarn.com/forum/showth...butor+balancer

Re: Balanced Rotor and Spring Grease
 

I'd forgotten about your balanced rotor, thanks for the reminder.
How many rpm does a rotor turn at say 2000 engine rpm?

Re: Balanced Rotor and Spring Grease
 

2,000 RPM crank speed = 1,000 RPM rotor speed.


What are the benefits of balancing the distributor rotor ?

Re: Balanced Rotor and Spring Grease
 

It removes the "whip" from an unbalanced weight on the end of the shaft, the same way counterweights help a crankshaft. I turned the bottom end of an old shaft to 3/8" and mounted it in my 1000 RPM drill and mounted a stock rotor, then a balanced rotor. You can feel the shake of the stock rotor, but it runs smooth with the balanced rotor.

Tomorrow I'll take a better picture and list the screw size.

Re: Balanced Rotor and Spring Grease
 

How about offsetting the side load on the upper bushing due to the point arm. I put a slave point arm on the opposite side to offset this force, but took it off because it was a pain to deal with when changing points. Just something to play with.

Re: Balanced Rotor and Spring Grease
 

"MAYBE" we should balance the OIL PUMP????
Bill W.

Re: Balanced Rotor and Spring Grease
 

Bill W. I remember when you tried to balance your wiper motor. You did a great job.

Re: Balanced Rotor and Spring Grease
 

Here's a couple more pictures. The screws are brass pan head 8-32 x 1/4 and the nuts are stainless hex. I used a drop of Loctite to make sure they don't come loose.

I used a thin cutoff wheel in my Dremel to trim away the excess Bakelite. I probably used a small diamond bit in my Dremel to make the screw holes. I wouldn't try a drill bit, as it may grab and snap the Bakelite. If you copy this picture, you will have a well balanced rotor.

Re: Balanced Rotor and Spring Grease
 

:eek:

Re: Balanced Rotor and Spring Grease
 

So long as you didn't change the width of the brass "finger" at the end nor weaken it too much around the rivet, you could lighten the other side by grinding away some of the heavy brass.

Re: Balanced Rotor and Spring Grease
 

Could we see a picture of the balancing set up? Thanks

Re: Balanced Rotor and Spring Grease
 

Reply #11 in this link has a picture of the balancer I made to do fans and rotors.
Just lay the upper shaft, with mounted cam and rotor across the ball bearings.

https://www.fordbarn.com/forum/showth...butor+balancer

Re: Balanced Rotor and Spring Grease
 

Tom, Thanks for sharing!