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Electronic Ignition. Trials and Tribulations
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simonA30



Joined: 19 Jul 2018
Posts: 23

PostPosted: Mon Feb 04, 2019 12:03 pm    Post subject: Electronic Ignition. Trials and Tribulations Reply with quote

I ensure that my 1954 A30 is started and run every few weeks at least. During the summer she goes for a few short runs. A few months ago she just wouldn't start. I have little knowledge of mechanics, and rely on the little I learned over 40 years ago. I tested to see if fuel was being pumped through, and all was OK. I then opened up the dizzy and noticed the points were not opening when I rotated the engine with the starting handle. The dizzy on an A30 is a pig to work on, but none the less I managed to get the points open and start the car. A week later I tried to start her, and the same thing happened. I then bought a new rota arm, condenser, and new set of points. Fitting them was tricky, and regardless of my efforts I just couldn't get the points open. To this day I still don't why.

After talking to a Mini enthusiast I was advised that putting in an electronic ignition module would make future life far easier, and the module in question would only cost about 35. I got myself on eBay and bought one. It was a piece of cake to fit. Simply take out the points and the condenser, put in the module, slip the magnetic rota over the shaft, and then the rota arm over that. Connect the red wire to the + terminal of the coil, and the black to the low tension wire, which connected through the loom to the - wire connected to the coil. Even an idiot like me found it easy. At this point I should make it known my car was converted to negative earth at some point in her life, and therefore purchased a negative earth module.

The instructions stipulate that the wiring MUST be correct, as if the two wires are incorrectly fitted, the module will fry. Well, everything connected I started the car. She ran very lumpy, but this was no surprise, as I knew the timing would now be out. Five minutes later and the car stopped. I tested for a spark but there was none. A friend of mine, who is a retired mechanic came and checked my installation and confirmed I had done everything correctly, and the module must be faulty. I returned the item and was sent a replacement. I fitted the new one, and the same thing happened. I then decided to do some proper research. Apparently if the two wires on the coil are NOT reversed when a car is converted to neg earth it doesn't matter if you have a points based ignition, however it does if you have an electronic ignition. At this point I took my multi meter out of storage and dusted it off. I put one end of the meter on the - wire and the other end to the low tension wire, but had no signs of resistance. I then did the same with the + wire and got resistance. This indicated the two wires simply needed reversing. I reversed the wires, sent back the 2nd module for a refund, put a new module on, and also a new coil, and started again. BINGO, all was well, especially after a bit of re-timing. What's more, it hasn't changed the appearance of the car.

So why have I spent all this time telling my story. Apparently the most common reason anyone has a problem converting to electronic ignition is because of these two wires, and I don't want anyone to go through the trials and tribulations I have. Other than that, I am informed life is a lot easier once this is fitted.
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consul 57



Joined: 09 Nov 2017
Posts: 218
Location: somerset

PostPosted: Mon Feb 04, 2019 12:10 pm    Post subject: Reply with quote

great news,
my mates zephyr mk2 was always a bit lumpyt and his is pos earth, he found the coil wires the wrong way round, once reversed it was fine!
i have yet to fit my elec ign, awaiting the warmer weather.
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ukdave2002



Joined: 23 Nov 2007
Posts: 3412
Location: South Cheshire

PostPosted: Tue Feb 05, 2019 12:52 am    Post subject: Reply with quote

Simon;Glad you are sorted, but lets dispel some myths!

1)Coil polarity is just as valid on a conventional traditional "Kettering" points ignition as it is with electronic ignition.

2)With either system reversed coil polarity significantly reduces coil HT output.

3)The term "Electronic Ignition" always conjours up thoughts of modern vehicle technology, in actual fact all the kits are based on what was called "Transistor Assist" systems that were fitted to production cars from the 60's

4)Using a transistor rather than the points to switch the coil current speeds up the collapse of the magnetic field of the coil; an exaggerated analogy is that points switch is like a slow puncture, whereas a transistor switch is a blow out; same energy but the blowout is much more intense.

5)You will only really benefit from fitting a electronic ignition if the plug gaps are opened up a tad; if left the same they will continue firing at the same voltage as with conventional ignition.

6)When you open up the points, the rest of the HT components will have to work harder, make sure the dizzy cap, leads etc are in good condition.

7)If the wrong polarity is applied to an electronic ignition kit, it wont be damaged, it just wont work at all.

8)The "Hall effect" sensors that replace points are sensitive, the gap is important as it effects both dwell and timing.

9)Finally if you fit an electronic kit to a vehicle that has a dynamo with electro-mechanical voltage regulation , fit a snubber to protect the transistors and diodes in the kit from high the transient voltages generated in the regulators.

Dave
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alastairq



Joined: 14 Oct 2016
Posts: 1165
Location: East Yorkshire

PostPosted: Tue Feb 05, 2019 1:55 pm    Post subject: Reply with quote

Thank you for that, Dave.

Can I add....I have replaced my sidevalve Ford points ignition with a hall effect system...very simple, very unobtrusive...and get a much 'cleaner' timing mark using the strobe....with points, the mark would be ''all over the place' at times....due to mechanical wear & tear, mechanical variations, etc.
There may not be much more in the way of 'power'...but the engine will be more 'efficient'...
However, my observation is, that I have come across one or two different after-market Hall effect points replacement kits....and one or two complaints.
The complaints focus on the ability of the Hall sensor to destroy itself if it should 'come loose'...
The factor I have come across, as to whether this occurs or not, surrounds the shape of the central rotating magnet, or 'interrupter'...
Most of today's kits have a circular magnet that fits over the distributor cam lobes.
But some older one's I have come across have a rectangular shape....
It is these latter items that I suspect can cause unwanted damage by virtue of the solid lumps whizzing around...if the sensor contacts these, destruction will undoubtedly follow.
Same goes for those which consist of a 'castellated' ring..[old Skoda Favorit, for example?]

The circular magnets by their very shape are unlikely to destroy any errant sensor.
Not that the sensor block should come loose, I hasten to add..but sometimes, things happen?
Unwise to forget the heat insulating grease under the sensor either.

These later ones [often available on eBay]....are easily replaced by the original points system, simply by removing the baseplate from the distributor, and having another baseplate, with points and condenser already installed, to hand. Before changing to hall effect, it may be wise to indelibly mark on the distributor, the 'points' timing position? Just in case?
_________________
Dellow Mk2, 1951 built, reg 1952.
Ford Mustang coupe, 1967, 6 cylinder auto.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.
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simonA30



Joined: 19 Jul 2018
Posts: 23

PostPosted: Sun Feb 10, 2019 12:39 pm    Post subject: Reply with quote

ukdave2002 wrote:
Simon;Glad you are sorted, but lets dispel some myths!

1)Coil polarity is just as valid on a conventional traditional "Kettering" points ignition as it is with electronic ignition.

2)With either system reversed coil polarity significantly reduces coil HT output.

3)The term "Electronic Ignition" always conjours up thoughts of modern vehicle technology, in actual fact all the kits are based on what was called "Transistor Assist" systems that were fitted to production cars from the 60's

4)Using a transistor rather than the points to switch the coil current speeds up the collapse of the magnetic field of the coil; an exaggerated analogy is that points switch is like a slow puncture, whereas a transistor switch is a blow out; same energy but the blowout is much more intense.

5)You will only really benefit from fitting a electronic ignition if the plug gaps are opened up a tad; if left the same they will continue firing at the same voltage as with conventional ignition.

6)When you open up the points, the rest of the HT components will have to work harder, make sure the dizzy cap, leads etc are in good condition.

7)If the wrong polarity is applied to an electronic ignition kit, it wont be damaged, it just wont work at all.

8)The "Hall effect" sensors that replace points are sensitive, the gap is important as it effects both dwell and timing.

9)Finally if you fit an electronic kit to a vehicle that has a dynamo with electro-mechanical voltage regulation , fit a snubber to protect the transistors and diodes in the kit from high the transient voltages generated in the regulators.

Dave


Thank you for your comments, you obviously know what you are talking about. I am especially grateful for the tip suggesting I open the plug gaps a little, as I will shortly do this. There are a few points you make though, that the manufacturer of the electronic ignition would disagree with. Here is a link to the Accuspark fault finding chart that indicates incorrect polarity doesn't make a difference to a points based system. - http://www.accuspark.co.uk/troubleshooting.html

I would also point out that the incorrect polarity when fitted to an electronic ignition will indeed damage it, and in fact burned out two systems on my own car before I reversed the wires. The manufacturers stipulate that the module will be damaged if the the polarity is wrong. Finally, Accuspark stipulate there must be a gap between the magnetic sensor and the module, but the size of the gap is NOT important, nor is one given
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