Multipole ring magnets experience

[pmbrunelle]

Best of all, there will be no fiddling around with the attachment of the disk and sensor trying to get the timing right.

Whether you are using points or using some other trigger, you will be using a strobe lamp to check the timing, and fiddling no matter what if the timing is not correct. With the rotary position sensor in the distributor housing(magnet on distributor shaft, rotary position sensor fixed to distributor base), you could adjust the timing in exactly the same way. Loosen the distributor hold-down clamp, and turn the distributor until the timing as indicated by the strobe matches whatever the ECU is commanding (some amount of advance you programmed).

Kettering ignition systems are repairable at the roadside with no more than a test lamp.  Even if you had a spare ECU, you would be most unlikely to be able to diagnose a wiring or sensor problem without a lot of test equipment.  Its not that Kettering ignitions are unreliable, its just that they need regular maintenance (clean and regap points, + a light smear of molybdenum disulphide grease on the cam) to remain reliable, and few car owners are willing to get their hands dirty now.

And maybe a file to clean up the points... but off you continue on your voyage.

With modern stuff, you get failures less often, but when stuff fails, you're far more screwed. I am not convinced that this is better.

As for a homebrew ECU, I believe it will fail as often as points, but you will be almost as screwed as when a modern fuel injected car doesn't run. At least until you iron out the bugs... which will take some time.

The MegaSquirt system I have on my car is of questionable reliability. I have about 60000 km on it though, and I have never been stranded. However, I often carry a laptop with me, and if I connect the laptop to the computer, then I can find a way home. For example, if you have a bad sensor input, you could tell the software to ignore that sensor, or to use a default value.

Worst case (this has never happened on the side of the road), I could edit source code, recompile, and reflash the microcontroller with new software if necessary.

So I think that the ability to change the software and/or calibration is more useful than to change the ECU; because if you want to limp home with some sensor/peripheral issue, changing the whole ECU won't do anything.

[Molenaar]

Kettering ignition systems are repairable at the roadside with no more than a test lamp.  Even if you had a spare ECU, you would be most unlikely to be able to diagnose a wiring or sensor problem without a lot of test equipment.  Its not that Kettering ignitions are unreliable, its just that they need regular maintenance (clean and regap points, + a light smear of molybdenum disulphide grease on the cam) to remain reliable, and few car owners are willing to get their hands dirty now.

I really don't mind getting my hands dirty, especially not if it solves the problem

Best of all, there will be no fiddling around with the attachment of the disk and sensor trying to get the timing right.

Whether you are using points or using some other trigger, you will be using a strobe lamp to check the timing, and fiddling no matter what if the timing is not correct. With the rotary position sensor in the distributor housing(magnet on distributor shaft, rotary position sensor fixed to distributor base), you could adjust the timing in exactly the same way. Loosen the distributor hold-down clamp, and turn the distributor until the timing as indicated by the strobe matches whatever the ECU is commanding (some amount of advance you programmed).

Kettering ignition systems are repairable at the roadside with no more than a test lamp.  Even if you had a spare ECU, you would be most unlikely to be able to diagnose a wiring or sensor problem without a lot of test equipment.  Its not that Kettering ignitions are unreliable, its just that they need regular maintenance (clean and regap points, + a light smear of molybdenum disulphide grease on the cam) to remain reliable, and few car owners are willing to get their hands dirty now.

And maybe a file to clean up the points... but off you continue on your voyage.

With modern stuff, you get failures less often, but when stuff fails, you're far more screwed. I am not convinced that this is better.

As for a homebrew ECU, I believe it will fail as often as points, but you will be almost as screwed as when a modern fuel injected car doesn't run. At least until you iron out the bugs... which will take some time.

The MegaSquirt system I have on my car is of questionable reliability. I have about 60000 km on it though, and I have never been stranded. However, I often carry a laptop with me, and if I connect the laptop to the computer, then I can find a way home. For example, if you have a bad sensor input, you could tell the software to ignore that sensor, or to use a default value.

Worst case (this has never happened on the side of the road), I could edit source code, recompile, and reflash the microcontroller with new software if necessary.

So I think that the ability to change the software and/or calibration is more useful than to change the ECU; because if you want to limp home with some sensor/peripheral issue, changing the whole ECU won't do anything.

I also often have a laptop with me and I will do sensor failure tests before I drive on the road. Default settings will certainly be implemented. But maybe I'll buy a dedicated laptop just to always be able to flash, to always have a charged one present.