30-07-2024, 05:34 PM
Hi John
To answer some of your questions I have dug out my notes from the recent rebuild. I measure the toggle holes as 1/16 inch diameter and their centres are spaced 3/16 inch apart. Most of the ones I have seen have a slight countersink, to stop wear on the spring ends presumably.
My two springs are identical and consist of 9.75 turns of 0.037 inch diameter wire. The length from the extremes of the ends is 0.807 inch, the length between the two inner faces of the end hooks is 0.733 inch. The latter stretches by 30 thou when installed and under initial slight tension, i.e. the installed length is 0.763 inches. Your photo is a bit fuzzy but the springs look to be 7 turns or thereabouts, so they may be from another model and be too strong.
I know you have taken it apart, but when reassembled can you easily prise the two weights apart and see the cam advancing ? The cam should be free to rotate on the spindle, there is a shoulder to stop the central screw from tightening it all up. Also, the weights should have spacer washers underneath so that they can pivot easily.
Distributor Doctor always emphasises that exact spring length and tension are critical, and difficult if not impossible to get right without actually having the unit on the bench.
The rim of the pulley on the camshaft is 4.25 inches diameter, and represents 720 engine degrees. If the distributor advances by its spec of 16 engine degrees that's a movement in the timing mark shown up by the strobe of only 0.3 inches.
To answer some of your questions I have dug out my notes from the recent rebuild. I measure the toggle holes as 1/16 inch diameter and their centres are spaced 3/16 inch apart. Most of the ones I have seen have a slight countersink, to stop wear on the spring ends presumably.
My two springs are identical and consist of 9.75 turns of 0.037 inch diameter wire. The length from the extremes of the ends is 0.807 inch, the length between the two inner faces of the end hooks is 0.733 inch. The latter stretches by 30 thou when installed and under initial slight tension, i.e. the installed length is 0.763 inches. Your photo is a bit fuzzy but the springs look to be 7 turns or thereabouts, so they may be from another model and be too strong.
I know you have taken it apart, but when reassembled can you easily prise the two weights apart and see the cam advancing ? The cam should be free to rotate on the spindle, there is a shoulder to stop the central screw from tightening it all up. Also, the weights should have spacer washers underneath so that they can pivot easily.
Distributor Doctor always emphasises that exact spring length and tension are critical, and difficult if not impossible to get right without actually having the unit on the bench.
The rim of the pulley on the camshaft is 4.25 inches diameter, and represents 720 engine degrees. If the distributor advances by its spec of 16 engine degrees that's a movement in the timing mark shown up by the strobe of only 0.3 inches.