Electronic Ignition
All stock Series Land Rover engines came with an inductive transfer or Kettering ignition system, a type which has hardly changed in basic principle since a brilliant engineer named Charles F. Kettering invented it at the Dayton Engineering Lab (a converted barn) in 1910. The business carried on in that barn grew into the mighty Delco company. Charles ended up at General Motors, had a distinguished career as engineer and humanitarian and eventually had a University named after him.
Most aircraft engines and high performance terrestrial engines employed magneto ignition. These are rotary devices which produce fatter sparks the faster they spin and don't need battery power, though they are not without problems and foibles of their own. However, the Kettering system ruled the world of everyday petrol engines for over seventy years and is far from dead today.
On associated pages:
The Defects of the Kettering System
On this page:
Can I update my Series Land Rover system?
Why electronic ignition?
Points/coil ignition was near-universal in petrol engined road vehicles for many years and steadily improved in the details of design and construction. A careful owner carried out the necessary maintenance or had it done for him, thereby keeping his engine in a good state of tune. Not-so-careful owners ignored the engine so long as it still ran and tolerated the poor fuel economy, degraded performance and difficult starting caused by their neglect.
By the late 1960's, the first laws were passed directing vehicle manufacturers to clean up engine emissions. To meet the legal requirements, engineers needed an ignition system which could keep to factory specifications between services. This meant getting rid of the wear-prone mechanical contact breaker set. In its simplest form, electronic ignition retained the conventional distributor with its mechanical spark advance, merely replacing the points with a non-wearing electronic means of sensing crankshaft position and firing the spark. Later analogue spark control computers had more sensors to gather information on throttle position, throttle opening speed, engine speed, manifold vacuum and coolant temperature. The spark advance was set by the computer rather than by a centrifugal unit in the distributor. Carburettors could be jetted for leaner fuel-air mixtures which burned more completely with less polluting residue. Today, at the end of the twentieth century, quite ordinary family cars have electronic engine management systems which have done away with the familiar distributor and carburettor entirely and allow previously unheard of performance and fuel economy.
Can I update my Series Land Rover system?
Your Series Land Rover is a survivor from an earlier time. The stock motor is not tuned for high performance and will run quite well with the stock ignition in good condition. An excellent move is to have the distributor run on a test bench by a competent specialist. These testing machines plot the advance curve against the manufacturers specs and can identify wear in bearings, centrifugal advance unit or ignition cam. A distributor which actually performs as new will unleash power and smoothness you did not know were there.
On the other hand, an add-on electronic ignition system will eliminate the need for frequent ignition tune ups and will deliver a slight but noticeable improvement in economy, power, smoothness and ease of starting. Some owners of later model de-toxed Series III's with factory-set lean fuel mixtures report greatly improved driveability. The most popular systems can be added to the existing distributor in your Land Rover, provided that the distributor bearings, centrifugal advance units, vacuum capsules, distributor cap and HT leads are in good order. Wobbly distributor shafts give inaccurate timing. Doubtful insulation will be breached by the higher energy available from breakerless ignition. The existing methods of ignition advance are retained. I know of no electronic advance system commercially available for Series ignitions.
Triggering Methods:
Hall effect: A semiconductor device using this principle produces a small voltage when a magnetic field is brought into its vicinity. The magnetic field does not have to move at all so the strength of the signal is dependent only on the strength of the field, not on the rate of change. Some Hall effect devices contain additional digital circuitry so that the output signal is a simple digital on/off or high/low, ideal for triggering a heavy duty power transistor which switches the coil primary current in place of the points.
If the Hall effect device is placed inside the distributor, a magnetic field can be arranged to pass across the sensitive area every time a triggering signal is required. The drawing below is the layout of the Bosch Hall Effect upgrade for Australian-made Bosch points-style distributors.
Other after-market systems, such as the Pertronix Ignitor™ have permanent magnets attached to a rotor which fits over the points cam on the distributor shaft, one magnet for each cylinder.
This American made electronic ignition is a popular upgrade for Lucas distributors used on Series engines. It has the advantage of combining the Hall pickup and the switching module within the distributor, so that a stock appearance can be retained without external control boxes. Buyers can use a stock coil or one of the Pertronix range of coils. The kits are easily fitted by the average owner.
Opto-electronic devices: These use a light-sensitive device opposite a light source with a slotted rotor interrupting the light falling on the sensor. It was an idea popular with experimenters in the 1960's who used visible light from ordinary incandescent bulbs and early light-sensitive photo-transistors. There were predictable problems with dirt, oil mist and vibration which gave optical systems a bad name. Today's systems are altogether different, using infra-red Light Emitting Diodes and Photodiodes in one integrated pickup unit requiring only power in, earth and signal out leads.
The British Lumenition system is made for a wide variety of distributors, including all Series Land Rover ones. It uses a pickup and chopper vane inside the distributor and an external swtching module.Reluctor pickups: Widely used in OEM breakerless distributors, including the Bosch unit I used in my non-Rover engine installation, but I know of no reluctor conversion kit for Series distributors. They have the advantage of being very simple and trouble free.
Black Boxes:
Homebuilt CDI: I made my first electronic ignition from a kit back in the 1970's. It was a Capacitor Discharge Ignition or CDI. This type did not rely on the collapse of the coil primary magnetic field to induce a high voltage pulse in the secondary winding. An inverter turned 12VDC into more than 400VDC which was stored in a capacitor. When the timing signal was received, a high current Silicon Controlled Rectifier or SCR abruptly dumped the capacitor charge into the coil primary winding. This gave a short, intense spark with a very fast rise time which had the advantage of reliably firing semi-fouled plugs in two stroke or racing engines. The disadvantage is that the fast rising voltage is easily induced into neighbouring spark plug leads, giving weak sparks in other cylinders when they aren't wanted. This "crossfire" resembles pre-ignition and can wreck engines. I gave up on my VW Bug installation and sold it to a friend who ran it for umpteen thousand trouble-free miles in a Ford Escort van until the electronics finally expired many years later.
CDI is out of favour today except in high revving two strokes. However, anyone who insists on having one can buy an assembly kit from Altronics, Kit Number K4370, Multi Spark CDI., $AUS110. It is an up-to-date design using fast power-switching transistors instead of an SCR and can be set to provide several sparks instead of one short one.Homebuilt High Energy Ignition: This is the one I used in my original Mustang Sally installation. The latest version of a very popular kit is available from Dick Smith Electronics, Kit Number K3303, High Energy Ignition for $AUS49.50. It is based on the Motorola Ignition Chip MC3334P, the data sheet for which can be downloaded here. The kit designer has modified Motorola's suggested circuit but the data sheet gives a good explanation of the theory of operation and its advantages. In its latest form, this kit can be built with trigger inputs for reluctor pickup, Hall Effect device or the existing points. The ignition coil can be any conventional type. The Motorola chip allows a fixed duration spark and extended coil primary dwell which gives a high energy spark at all engine speeds. With its choice of inputs, this ignition module could be used with any Hall Effect or reluctor device that can be adapted to your original distributor.
Note: These assembly kits are just what the name implies; a packet of individual electronic components which you solder to a circuit board yourself. Some electronics assembly experience is essential.
Users Feedback:
You can have your comments HERE. Email me if you have used any brand of electronic ignition on a Land Rover.Tell me where you bought it and how it worked for you. Your fellow Rover owners will enjoy reading about it.
Links:
Dick Smith Electronics : on-line assembly kit buying.
Altronics : on-line assembly kit buying.
Pertronix Ltd. : US maker of Hall effect electronic ignition kits.
Autocar Electrical Equipment Co.Ltd. : British maker of Lumenition opto-electronic ignition kits.
Addresses:
Barsby Spare Parts : New, used and reconditioned Holden Parts
Gympie Rd.
Tinana.
MS1542, Maryborough, Qld 4650, Australia
Phone (07)4122 3855 Fax (07) 4121 6807
