Well I bought the latest VWMA Mag to read the article on the dizzies and well was somewhat disappointed. Not what I was expecting so A started thinking about dizzies and how they worked and advance curves etc and thought what I really needed was a dizzy tester. Something that would empirically test and map the performance of a given distributor. Given I've got a few dizzies lying around and I know at least one of them is shagged it would be nice to make it good again. Soooo I'm thinking about haveing a go at makeing a tester something that would allow me to repeatedly read the advance for a given rpm and also a given vacuum as well. Today I had to sit through a 4 hour mandatory training session at work on a particular irrelevant topic during a break I grabbed a pad of paper and pen and started noting down some ideas etc on how I could put one together. A quick google showed on different automotive forums a few other people expressing a desire to build one and the usuall response was "just buy and old Sun unit" and there was some reference to a wooden unit in a popular mechanics magazine from around the time of Noah and not much else. As old Sun units are few and far between I figured it can't be that hard to knock up a modern version. I've got some ideas as to how to do it and do it cheap and easily with high accuracy but want to put it out to those that know what features such a device should have. Some critical parameters I'm thinking of are. RPM Advance at any specified rpm Advance at specified vacuum What do others think is there other things that would good - determining dwell perhaps or amount of points bounce, consistency of advance between cylinders?