Those of us who make starters would like all the electronic start retards to go away. Please.
While the rotor phasing is a concern, it usually doesn't cause a big problem unless you are retarding 20 degrees or more AND using a small distributor cap (assuming the phasing was at least reasonably close to begin with).
The real problem is the way in which the timing is retarded during cranking when using electronic timing retard.
Most traditional distributors have a form of "start retard" but they start out with the timing retarded and then added more advance as the engine rpm increases by using weights and springs. This is a better way to prevent kick-back during cranking than an electronic retard (which starts out with the timing advanced and then attempts to retard the timing during cranking). There are also distributors/ignitions that have electronic advance and they work fine as well. It's just the electronic start retard that causes problems sometimes.
Unfortunately, some engines use a crank trigger (or a distributor without a mechanical or electronic advance) so the timing is locked in the fully advanced position. This can make cranking the engine with the starter difficult. So the aftermarket ignition companies added electronic start retard as an option to some ignition systems/boxes. In theory this works fine, but in reality it sometimes makes kick-back worse, at least part of the time.
While rotor phasing is a concern, the big problem is how the ignition calculates how much to retard the timing. When cranking the engine, the ignition doesn't send any current to the plugs until the the pickup in the distributor (or the crank trigger) sends out about three or four pulses to the ignition box. Then, by taking the average time between pulses, the ignition calculates how much (in fractions of a second) the timing should be delayed to get the desired amount of start retard. Then the ignition starts sending current to the plugs. Once you let go of the starter switch (or the engine reaches a certain rpm), the ignition stops delaying the sparks. This should work fine but often doesn't.
The ignition uses the average time between pulses to do the calculations. Unfortunately, unless the engine cranks at a very consistent rpm, the average time calculated from a sample of only three or four pulses will not be very accurate, especially on a high compression engine where the starter speed varies as the engine rotates. The ignition then uses this inaccurate data to calculate how much to retard the timing during cranking. Sometimes the data is so bad the ignition is retarded way too much or not nearly enough and the engine kicks back, often breaking starters and ring gears. The ignition companies could make the calculations more accurate by allowing more pulses before sending current to the plugs but if the starter cranks too long before starting the engine, the battery might start to get weak (plus customers would complain about long cranking times).
There is a low tech solution for engines with locked timing. Install a second ignition pickup/trigger in the distributor (or add a pickup to the crank trigger distributor if running a crank trigger) that is retarded about 15 or 20 degrees compared to the other pickup/trigger. Then, using a double throw switch, fire the engine on the retarded pickup and then switch to the advanced pickup once the engine is running. Simple, works great, not expensive. But I have trouble getting people to try it. So, at the very least, turn the ignition off, get the engine cranking, and then turn on the ignition. Just please, don't use electronic timing retard. While it may work just fine 50 times in a row, every now and then (say when the battery is a little low on charge)it is going to cause a nasty kick-back.
