www.jec.org.uk

seems to be a lot of myth and legend around these topics from issues with certain electronic ignition units causing problems with the tacho and with some dodgy rotor arms.

Anyone know the truth about these and any suggestions?
There looks like a nice simple electrionic ignition system on ebay item no 310197839960 - any thoughts?

Mark.

Mark, this may not answer all of your questions, but this is what I know.

There are 5 basic types of electronic ignition system. These are, in order of increasing cost:

1. The original points are retained, but a switch module is use to reduce the current in the points, so prolonging their life. The switch module is external to the distributor (now rare).
2. The points are replaced by a sensor, either magnetic or opto-electronic. The switch module is integrated with the sensor (like the Accu Spark unit shown on ebay)
3. As for 2, but the switch module is external to the distributor (Pertronix, Lumenition etc).
4. As for 3, but the external switch module is replaced by a Capacitor-discharge unit, which feeds several hundred volts to the Coil Primary.
5. The sensor and switch module are integrated into a purpose built distributor (‘123’, some Pertronix etc).

The environment surrounding the inition system is very harsh, especially for electronics. Heat, high voltage and high currents are not good bedfellows.

For type 2 systems, where the sensor and switch module, are integrated and fitted to a standard distributor the electronic components need to be rugged and well spec’d. They should work but it is a possible weak area.

All systems, when correctly fitted should be reliable and there should be no problems with Tachos.

So, why do people have problems? In my experience, they are not wired correctly and/or the system is not matched to the coil fitted. Standard coils should be OK but some Sports coils present too low a resistance for the switch module to cope with long-term.

You are urged to study Installation notes before purchase.

I have had a Lumenition opto-electronic system fitted to my car for about 15 years and it has been very reliable and money well spent!

That said, I have had a number of ignition system problems: all relating to the Rotor Arm.

This is probably the cheapest single component, which when it fails can completely immobilise a car.

There has been much written in JE over the years about Rotor Arms.

When we had the much missed ‘Reproduction Parts Programme’, that sub-Committee did great work, in alerting members to problem components and even forcing maunufacturers to change their Specs., when in error!

It should be noted that some Electronic Ignition systems produce greater HT voltage than Standard systems and this does impose an additional burden on the Rotor Arm and HT wiring, and can result in insulation breakdown. This breakdown usually starts in an intermittent way but soon it will be terminal.

Perhaps the best advise is to take note of recommendations of successful systems, but to be sceptical of reports of failure, where poor installation or choice might be the cause.

Mark, this may not answer all of your questions, but this is what I know.

There are 5 basic types of electronic ignition system. These are, in order of increasing cost:

1. The original points are retained, but a switch module is use to reduce the current in the points, so prolonging their life. The switch module is external to the distributor (now rare).
2. The points are replaced by a sensor, either magnetic or opto-electronic. The switch module is integrated with the sensor (like the Accu Spark unit shown on ebay)
3. As for 2, but the switch module is external to the distributor (Pertronix, Lumenition etc).
4. As for 3, but the external switch module is replaced by a Capacitor-discharge unit, which feeds several hundred volts to the Coil Primary.
5. The sensor and switch module are integrated into a purpose built distributor (‘123’, some Pertronix etc).

The environment surrounding the ignition system is very harsh, especially for electronics. Heat, high voltage and high currents are not good bedfellows.

For type 2 systems, where the sensor and switch module, are integrated and fitted to a standard distributor the electronic components need to be rugged and well spec’d. They should work but it is a possible weak area.

All systems, when correctly fitted should be reliable and there should be no problems with Tachos.

So, why do people have problems? In my experience, they are not wired correctly and/or the system is not matched to the coil fitted. Standard coils should be OK but some Sports coils present too low a resistance for the switch module to cope with long-term.

You are urged to study Installation notes before purchase.

I have had a Lumenition opto-electronic system fitted to my car for about 15 years and it has been very reliable and money well spent!

That said, I have had a number of ignition system problems: all relating to the Rotor Arm.

This is probably the cheapest single component, which when it fails can completely immobilise a car.

There has been much written in JE over the years about Rotor Arms.

When we had the much missed ‘Reproduction Parts Programme’, that sub-Committee did great work, in alerting members to problem components and even forcing manufacturers to change their Specs., when in error!

It should be noted that some Electronic Ignition systems produce greater HT voltage than Standard systems and this does impose an additional burden on the Rotor Arm and HT wiring, and can result in insulation breakdown. This breakdown usually starts in an intermittent way but soon it will be terminal.

Perhaps the best advise is to take note of recommendations of successful systems, but to be sceptical of reports of failure, where poor installation or choice might be the cause.







Very well put.

I bought the +ve earth Pertronix electronic system 5 years ago matched to the Flamethrower coil for my '61 roadster and it works perfectly.
The system is very neat and fits inside the dizzy cap and is also cheap.

I did consider buying the 123 +ve earth system, however because the Pertronix works I thought best leave well enough alone.
A lot of my friends have the 123 and say its a very good system.

Dave

so, If I get this right, rotor arms just fail when warm, does anyone know why and how to detect one that is likely to do that?

As for ignition systems, anyone know where to get a distributor baseplate for for a 22D6 dizzy too? Mines a little worn.

Mark

I had my dizzy overhauled at Holden near Hereford and they did a very good job. Do a search for Holden on Google and it should throw up a website address.
They have now end of spares for all sorts of classic and vintage cars.

Dave

A few words from JE 2003 etc

LINK