Couple of things to tinker with here. The wear between the gear and the bottom of the distributor body shaft can only really be corrected by removing the gear, removing the guts, and shimming under the shaft itself. Installing shims between the gear and the distributor body shaft, common with the V8 distributors, actually moves the breaker plate pretty high, sometimes way too high, from the distributor lobes. So what you might try is loosening the clamp and pushing down on the distributor body which my help take up some of the slack.
What number is your distributor? The reason I ask is that the early distributors did not have the spring and Bakelite pad arrangement as part of the grease cup. As far as I know this was a later addition to help with shaft stability as it wore. If your shaft is really worn, and does not have the spring arrangement, a wobble might be what is causing the fluctuation. There are no bushings in these distributors.
You might also consider pulling the distributor out, take it apart as far as you can, and give it a through degreasing and inspection of the advance weights. Pay particular attention to the springs and whether the pins are tight, the springs are both in place, and the weights are free and working. Lube the weights with some light oil, grease the springs and pivot points with grease (I like the red or blue stuff myself), then put it back together and reinstall, making sure you press the body down tight before tightening the clamp. Recheck the point gap and install. Get the motor running and put a dwell meter on it and make sure the dwell is within specification. Then check the timing and see if it is still fluctuating.
Last edited by Dragsix; 12/27/2020 4:59 AM.
