Mechanical advance in old school C5AF-E distributor

[dcdoug]

Originally Posted by Rick Parker

As Wayne described the light springs will often allow the weights to move at a relatively low RPM or because they allow static movement of the weights with the springs fully retracted. This will cause some of the available advance to be initiated before you get above the actual idle speed, thus limiting you to only have available 17 or 18 degrees of distributor advance. Sometimes because they have very little tension (light springs) the timing will fluctuate at low idle speed causing the idle to "Hunt" ie: raise up and down a little as the timing moves up and down a couple of degrees, this becomes worse and more exagerated with a long duration cam, open plenum manifolds and big carbs. The tangs on the base plate (attached to the shaft) can be moved a little to take up some of the free length of the spring and tweak the advance rate a little. If you are near a shop with a distributor machine (old school) it is much easier to create the curve you desire. Doing this is a dying art.

I spoke to a number of Ford distributor rebuilders last week looking for a few fasteners, etc that I wanted to replace and I'm sure a few of them could help me if I can't figure it out. One guy named Tim O'Connor seems to have a particular long time passion for Ford distributors. I spoke with him a couple times. That might be a winter project if I can't get it dialed in over the next month or so. It is an interesting subject and I'm not sure why there's not more written about it. I guess everyone has just gone to MSD/Mallory.