Posted by Gary-Virginia
I dont know if this has been covered before, or recently, but I would like to relay my experience in properly setting up early style distributors.
I went to the local scrapyard and purchased a piece of aluminum sheet that had been cut in a circle 8.25 inches in diameter. Using a set of dividers, I scribed 32 lines in the sheet, dividing it into 11.25 degree sections. Then I cut a hole in the exact center that was the same daimeter as the flange on my 37 distributor.
Using the dividers, clamped to the tab that fits the slot in the camshaft, I created a fixed rotating pointer. With the disc on the back of the distributor in the same position as the piece on the engine it bolts to, with my marks facing rearward, I can rotate the dividers and precisely measure the timing of the distributor.
I set up an ohm meter, and with my finger on the rotor creating some drag to keep the centrifugal advance form working, I can precisely check each set of points for their proper amount of opening degrees. After setting up each set of points individually, I check for the perfect 11 degree simultaneous opening of both points which is the real secret to getting this distributor working as well as it can. The rotation is counterclockwise, the leading set of points should open about 10 degrees before the trailing set of points. When the trailing set opens the spark occurs, the closing of the leading set 11 degrees later, completes the spark part of the cycle. Set each point correctly at 21 degrees, then check for your 11 degree both points open condition, this is more important than the gap of the points. Fine tune your point adjustment to get equal duration on each point set, and the 11 degree combined opening of both points. When you have this set up properly, with a decent condenser and coil, you can be assured the ignition is functioning as well as it is capable of.
I tried setting points without checking the things mentioned above but the method above is much more precise. The materials to make the tool cost nothing, I had seen a couple of timing fixtures on EBAY but the prices were hard to justify when you consider how few times you would use such a tool.