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Old 01-26-2017, 09:57 PM   #1
Tom Wesenberg
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Default 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
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File Type: jpg Timing Rotor Position.jpg (66.7 KB, 153 views)
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Old 01-27-2017, 12:52 AM   #2
Chuck Sea/Tac
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Default 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?
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Old 01-27-2017, 01:55 AM   #3
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Default 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 ?
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Old 01-27-2017, 02:19 AM   #4
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Default Re: Balanced Rotor and Spring Grease

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Originally Posted by Special Coupe Frank View Post
2,000 RPM crank speed = 1,000 RPM rotor speed.


What are the benefits of balancing the distributor rotor ?
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.
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Old 01-27-2017, 08:34 AM   #5
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Default 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.
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Old 01-27-2017, 12:00 PM   #6
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Default Re: Balanced Rotor and Spring Grease

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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.
"MAYBE" we should balance the OIL PUMP????
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Old 01-27-2017, 12:29 PM   #7
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Default Re: Balanced Rotor and Spring Grease

Bill W. I remember when you tried to balance your wiper motor. You did a great job.
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Old 01-27-2017, 02:55 PM   #8
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Default 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.
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File Type: jpg Rotor Balnced 1.jpg (43.8 KB, 83 views)
File Type: jpg Rotor Balanced 2.jpg (45.1 KB, 87 views)
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Old 01-27-2017, 02:59 PM   #9
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Old 01-27-2017, 03:50 PM   #10
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Default 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.
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Old 01-27-2017, 07:09 PM   #11
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Default Re: Balanced Rotor and Spring Grease

Could we see a picture of the balancing set up? Thanks
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Old 01-27-2017, 08:07 PM   #12
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Default Re: Balanced Rotor and Spring Grease

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Could we see a picture of the balancing set up? Thanks
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
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Old 01-28-2017, 07:58 AM   #13
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Default Re: Balanced Rotor and Spring Grease

Tom, Thanks for sharing!
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