The whole E-timer concept brings up new questions for me, along with surfacing of prior questions I've had. For example:
Does the Compression Ratio of a low head, high head, or Z head affect the optimum advance curve?
I am sure my Fronty R head's optimum advance is less than for any flathead, but I haven't done the testing to know for sure. I just use the 26 +/- 4 degrees advance built into the Porsche 914 disturbutor I run. I have and could run manual advance as well, but it's not clean and easy with the Atwater-Kent front plate I'm running.
When I ran a flathead, I modified a 914 disturbutor centrifugal advance to top out at lower rpm, thereby steepening the curve. It seemed to work pretty darn good, although it was seat of the pants testing.
I asked on a prior thread on the E-timer if anybody had optimum advance curves for the T, but no reply. The cleanest way to do it would be with a dynamometer, but not everybody has one, and there likely would be some differences between similarly equipped cars.
It doesn't seem to be general knowledge how much engine power is lost with the Ford "Steady by jerks" ignition, but E-timer testers indicate it's a lot. Can all of that Ford ignition power loss be avoided by running 12 volts to the buzz coils, and careful manual advance?
Can the timing be optimized with a manual advance disturbutor running on six volts?
Is manual, seat of the pants, advance as precise as automatic centrifugal advance?
Vacuum advance, which is always additive to automatic centrifugal advance, provides more advance at partial throttle for better fuel economy. I need to put the vacuum pot back on the disturbutor in the Fronty. You can approximate, or even maybe do better than centrifugal advance with manual advance, but it's maybe not so easy to match vacuum advance.
The E-timer is a clever concept and admirable effort, and gives T owners one more option. Thank you, Mike Kossor.