Tailored especially for vintage and classic automobiles

Contact: Winterburn Ignition at winterburnignition@gmail.com

        The Winterburn Capacitor Discharge Ignition System was the very first commercially successful solid-state CD ignition designed by the late Lloyd Winterburn (RCAF electronics expert and pilot) in 1962. It solved the problems that had plagued earlier design attempts and became the most copied design throughout the 1960s and 1970s. The first production units were manufactured by Hyland Electronics of Ottawa Canada in early 1963. Many Hyland ignitions are still functioning more than 50 years later. The Winterburn designed CD ignition is being manufactured again by Lloyd's son, Fred Winterburn, in small quantities with 12V and 6V models available. All units are hand built utilizing high quality components with high voltage and current ratings. The power supply transformer, which is the heart of the unit, is wound by hand to exacting standards (a time consuming process). Each unit contains over $180 CDN in parts and takes in excess of 6 hours to build. I will sell to most countries or persons. Exceptions noted as of February 2023 are: North Korea, Communist China, The Russian Federation, South Africa and Justin Trudeau.


         The design retains the basic elements that worked so well on the Hyland, but with a long duration multiphase spark. It is compatible with positive or negative ground cars and hookup is exactly the same regardless of the polarity. For example, if one is installed on a positive ground car and the car is converted to negative ground at a later date, no changes are required. The CD circuitry will automatically adjust to the new polarity. There is an o-ring sealed switch provided to revert back to standard (Kettering) ignition if need be.

         There are very good reasons why this CD ignition is intended to be triggered by distributor points. When points do not have to break the heavy current of the Kettering system they will last a very long time, often in excess of 60 thousand miles providing the rubbing block and distributor cam are lubricated occasionally. The points are not voltage sensitive as they are a simple mechanical switch. This allows the Winterburn CD power supply to provide almost full spark energy down to *3.5 volts(6V model) to start a car with a weak battery. This is true for any car with points regardless of manufacture, as points do not have a threshold voltage requirement as do some other triggers. The CD circuitry cancels the effect of points bouncing upon closure, so despite still being present when triggering the CD ignition, high engine speeds are possible without spark scatter. This ability was a key feature of the original Winterburn patent. Finally, retaining the points gives the redundancy of two types of ignition systems. If the CD fails (very unlikely), or troubleshooting is required, the ability to switch easily from CD to Kettering is a boon. The switch is provided to make that easy. The switch also has a centre 'off' position.
6V models will provide a healthy starting spark (approximately 22kV) down to 3.5V battery voltage, and 12V models will provide the same at 5.5V when using a conventional coil.    

         12V units can be triggered by Pertronix/Aldon Ignitor. Pertronix Ignitor 1,2 reliably(not compatible with pertronix 3) Ask for instructions as the Pertronix hooks up differently, and only negative ground Pertronix modules are suitable triggers. Also, to protect the switch on the CDI, only use coils with primary resistance 1.2 ohms or greater.  6V units can be triggered by 6V Pertronix/Aldon, but it is not recommended due to the high minimum voltage requirement of the Pertronix/Aldon.
         12V and 6V units can be triggered by 123 brand electronic distributors as well as many other electronic ignitions that switch coil current on the ground side of the coil.

      The Winterburn CDI is voltage controlled to limit insulation stress to vintage ignition components. It's current (amperage) that lights fuel, not voltage. Spark power is controlled to ensure spark plugs and high voltage contacts have life expectancies exceeding those of today's automotive ignition systems. Excessive spark energy with high peak spark power, can wreak havoc with stock ignition components and this is a problem with most* high energy CD ignitions on the market today. The Winterburn CDI strikes a balance such that stock components last longer than with the Kettering system, while greatly increasing performance.

*(One popular manufacturer of CD ignitions claims a very high voltage output, but actually has a  low voltage product with a weak, short duration spark, for which its abilty to multi-spark can't compensate for, based on my testing)

      This ignition system provides high power to fire wet, gasoline soaked, or carbon fouled spark plugs. Testing with a shunt resistance of 126 thousand ohms bridging the spark gap to simulate a severely fouled spark plug, reveals the Winterburn CDI provides more than ten times the spark voltage than if the same ignition coil is used in the conventional manner (Kettering or Transistor switch). With a shunt resistance of 625 thousand ohms simulating a less severely fouled spark plug, the unit will provide up to double the spark voltage compared to Kettering or Transistor Switch systems. This feat is accomplished with a total available voltage slightly less than the Kettering system or Transistor switch systems. It's this near immunity to shunt resistance that means the difference between a flooded engine (Kettering or Transistor switch) or an engine that starts on the first compression (Winterburn CDI). Cold weather starting is vastly improved, and as a bonus, some cars that are notorious for hard starting after being run in hot weather, start more easily with this ignition system. To put this in perspective, with modern engines having very high energy inductive ignition systems, and much higher available voltage, plug fouling is said to begin at about 10 million ohms shunt resistance. If the shunt resistance drops to 1 million ohms, the affected cylinder will misfire continuously. With this CD ignition, an engine will run without misfires with a shunt resistance of 1 million ohms.

Efficient power supply design means very little heat generated by the unit itself and power consumption is very low. 12V units consume 3 amps at 8000 rpm on an eight cylinder car, and 6V units consume 4.3 amps at 8000 rpm. With a CD ignition, current draw increases with RPM which is the opposite of the Kettering system, so power is only used when it is required.  A four cylinder engine driven briskly with a 12V Winterburn CD will average just over 1 amp current draw. This makes it ideal for cars with small capacity charging systems and prolongs the life of the contacts in the car's ignition switch. Despite the low current draw, the power output is still very high. This is undoubtedly the most efficient CD ignition on the market today. Gains in efficiency, and spark duration, are accomplished by tuning the circuit to match most standard production ignition coils. The CD power supply, in addition to its primary function of charging the CD discharge capacitor between spark events, also provides extra energy during the spark period which prolongs the natural resonance, and hence spark duration. The Winterburn CDI has a long multiphase spark up to 0.5mS long depending on the ignition coil. The canister style coil that is already on your car is a good choice. It is perfectly acceptable to use a coil with high primary resistance (up to 3.6 ohms) as the reduction in spark energy is less than 7% over a coil with 0.7 ohms primary resistance.

Reliability: Torture testing has proven that any of the failure modes for which other designs are susceptible, do not damage the Winterburn CDI.
-The dual polarity feature makes it almost completely immune to improper hook-up *See note 3 below.
-The novel power supply design unique to this model, limits the voltage output to prevent damage to the SCR and other voltage sensitive components should the car's voltage regulator fail and drive the supply voltage excessively high. This is done without any extra components that would complicate the circuit and create potential failures in themselves (no zener diodes or conventional voltage regulation methods are employed). This was a mandatory design feature for the 6V unit should it be connected to, or boosted from a 12V source. It also benefits 12V units.
-The power supply also starts oscillating at a very low, 1.5V battery voltage. This prevents overheating of the power supply transformer and transistors from resistive heating due to 'lock-up' of the power supply oscillator. It's also part of the reason for 6V units having the ability to throw a starting spark at 3.5V (guaranteed, as most units will do so at 3V with resistive spark plug wires)
-In common with the old Hyland design, the power supply also reduces its power output once the load increases beyond a certain point.
-Units have been tested with the output dead shorted for hours without damage. (Bosch units and others fail in short order when this happens).
-Simulated tests of coils with secondary windings shorting to the primary winding do not result in damage to the CDI.
-No electrolytic capacitors are used; only film types with high temperature, voltage and moisture ratings.
-Some CD ignitions are notorious for generating excessive heat and require cooling fins to dissipate that heat. The Winterburn Ignition generates very little heat even at the highest possible engine speeds.
-The Winterburn CDI is not potted. This allows it to be repaired in the unlikely event that is required. Since the unit is not potted, any components vulnerable to vibration are further supported with a special long lasting adhesive. Retaining a robust analogue design, utilising standard discreet components rather than specialized integrated circuits, ensures continued parts supply long into the future.

The Winterburn CD Ignition will give results that points replacement type electronic ignitions can't, such as Pertronix, which are modern day transistor switch ignitions. (It will also yield results that a poorly designed CD ignition can't either!) A properly built CD ignition cannot be hidden within the confines of a distributor. The size of the discharge capacitor alone would be a tight fit. (The unit measures 5-5/8'' (15cm) long at the base plate, by 3-1/8" (8cm) wide, by 3" (7.5cm) high to top of switch knob). Weight is approximately 2.2 lb (1kg).  

Expect a minimum of 5% fuel savings with increased power and very easy starting while increasing the life of your original ignition components. An 8 cylinder car driven 5000 miles per year with the Winterburn CDI can be expected to pay off the initial cost in a maximum of 5 years at today's fuel prices. That doesn't factor in the increased reliability, throttle response, and reduced engine wear from complete combustion.

The Winterburn long duration CDI comes in a 'splash resistant' cast aluminum case painted with three coats of black paint over two coats of zinc chromate primer. The base is natural aluminum. The aluminum nameplate utilizes the Aluscreen process for durability. It is designed to look 1960s retro to augment the underhood appearance of classic cars. It can be hidden if that is desired. It will operate properly with any type of ignition wire and is compatible with resistor spark plugs. It will also trigger RVI (Smiths) and voltage sensing tachometers without a special tach adapter in most cases*. Enquire for compatibility or I will ask what you have for a tachometer if you don't ask first! Newer voltage sensing tachometers will function in both CDI and Kettering modes with the tach sensing wire connected to the green CDI wire. Most early voltage sensing tachs require an adapter to provide the high voltage needed for the tach input. Due to issues with some adapters on the market, I build a simple adapter that allows early type voltage sensing tachometers to function properly with the switch on the CDI in either 'CD' or 'STD'. This adapter works equally well with 6V or 12V tachometers. Price is $70 Canadian. An alternative adapter that works well with 12V VDO tachometers with the switch on the CDI in either CD or STD can be found here: http://www.ashlocktech.com
 *The later style Smiths RVI with the sensing loop internal to the tachometer (single transistor type) may require a conversion to the voltage sensing type to be compatible. The early two transistor Smiths RVI current sensing tachometer (external sensing loop) can be made to work easily with the addition of a $2 bridge rectifier. 

10 Reasons Why You Should Try a Winterburn CDI

1.  3% to 4% more HP over most of the RPM range over points or Pertronix on mildly tuned engines. More with performance engines. *See note 1 below.

2.  Improved throttle response (power delivery more immediate when pressing the accelerator pedal).

3.  Much better fuel economy. Varies with engine, but in rare cases has been as high as 25% improved. (an example is a 6V, VW Beetle)

4.  No power loss at high RPM.

5.  Useful spark duration is long enough to fire even very lean mixtures unlike most CD ignitions. Most multi-strike CD ignition systems have spark durations of between 35 and 100 micro-seconds. The useful spark duration of the Winterburn system in the worst conditions is never less than 350 micro-seconds.

6.  Cold and Hot starting much improved. The nature of the Winterburn CD power supply is such that the voltage output for starting is almost independent of battery voltage, so that on 12V systems an engine can be started with nearly full spark energy down to 5.5V (3.5V on 6V models).  (Most CD ignitions sold today do not have built-in compensation for low battery voltage, so the CD output voltage drops in proportion to battery voltage).

7.  No drop off in idle speed as CD ignition resists spark plug fouling and cleans spark plugs at idle when most carburetted engines tend to run slightly rich. (you may have to reduce the idle speed slightly with some engines, as the faster growing flame kernel results in a more stable and consistent flame front). With fewer misfires and more consistent combustion between cylinders, idle is smoother too. Superior running in wet conditions as spark plugs will still fire with insulators completely submersed in water.

8.  Spark plugs last as long, or longer than on modern cars.

9.  Breaker points last over 60000 miles, and all other stock ignition components last longer than when used inductively. Standard copper core ignition wires can be used with great success unlike some other CD ignition systems. 

10. A switch, (quality, USA made, and the most expensive single component of the ignition system) to revert to standard ignition for troubleshooting, setting dwell for use in STD (non-CD mode), or in the unlikely event the unit fails. The switch is 3-position with a centre 'off' position that completely disconnects all parts of the ignition circuit. This can be used to help deter theft.


Note 1: In very few cases, the owner may not notice a performance improvement over a system using brand new spark plugs and other new ignition components. However, over time, as spark plugs and other components degrade from use and age, performance will not drop off nearly as quickly with the Winterburn CDi. Spark plugs last at least 5 times longer and won't foul, while high voltage insulation is protected better than with the standard Kettering system or points replacement modules. 

Note 2: The Winterburn CD ignition will complement your existing ignition system components and accomplish all of the above (in most cases, see note 1) with a spark superior to that found on modern cars, but it can't compensate for already failing ignition components (such as plug wires) or a worn out distributor.

Note 3: Failure to follow directions during installation can result in damage to the switch on the CDI. If the supplied instructions are followed and warnings heeded, this cannot happen and the switch will last indefinitely.

Note 4: Some very expensive and also some inexpensive CDIs currently on the market are sensitive to dwell (points gap). Some will fail to trigger the CDI with too little dwell and some with too much dwell, or both. For example, on dual point distributors, some require removing one set of points to reduce the dwell. Not only does this limitation affect operation with breaker points, it also means that those CDIs can't be triggered reliably from some electronically switched inductive ignitions. The Winterburn CDI is not finicky with dwell and so far has been able to be triggered by any electronic ignition that normally switches coil current on the ground side of the coil. This includes Pertronix Ignitor 3 which is a multispark ignition. Note that to protect the switch on the CDI when selected 'STD', that the coil primary resistance should be no lower than 1.2 ohms.

The current price per unit as of July 2022 has increased by $30 Canadian to  $495CAD due to increased inflation (3.25% per year increase)  (Last price increase was August 2020). I build these units in small batches, and as such, there may be a short wait before more become available. You can reserve from the next batch with no down payment if you don't mind waiting. Each unit has a 25 month warranty.

New for August 2022 is an improved 6V unit. Although I had no complaints with the existing design, I wanted to improve the rpm capability and low battery voltage capability of the 6V unit. The result is a very efficient CDI that will provide a starting spark at 3V battery voltage(formerly 3.5V) and provides a 30% higher spark rate at 6V than the previous design. This ensures there will be no misfires if the car's charging system fails with the ignition subsequently being run by the battery alone (6V or less as opposed to 7.3V with the generator charging). It will also provide the spark rate required by higher revving 12 cylinder cars.                                           

For more information, Contact Fred Winterburn, RR3 Ripley Ontario Canada N0G-2R0, tel: 519-395-3483 or email winterburnignition@gmail.com 

About voltage rise time: The advantage of CD ignition in firing fouled spark plugs has been traditionally attributed to a CD ignition having a very short voltage rise time, or more correctly, a fast voltage rate-of-rise. It was pointed out to me sometime ago that this only applies when a CD ignition is compared to the Kettering system that uses a condenser. When the coil primary current in an inductive system is switched by a transistor with no condenser in the circuit, the voltage rate-of-rise is comparable to when the same coil is used with a CD ignition. The condenser in the Kettering system slows the voltage rise by 1-1/2 to 3 times depending on the coil used. The opinion of the person who pointed this out to me, was that since the voltage rise wasn't really any faster with CDI, that meant that CDI was no better at firing fouled spark plugs. That would be a reasonable conclusion except that the voltage rate-of-rise with CDI is actually much faster when presented with a load. Prior to spark formation, the only load is the amount of energy required to alter the magnetic flux of the coil and a small amount of current that crosses the spark plug electrode in the form of a corona discharge. It takes very little energy to accomplish this, so the unloaded voltage rise is very quick in either case. (Compare it to a car with the driving wheels jacked off the ground. It takes a certain horsepower to overcome the friction and mass of the driveline to bring the wheel speed up to 100 mph in a certain time period. A 100 hp engine will bring it up to speed almost as quickly as a 300 hp engine will. Put the wheels back on the ground and it's a much different story). When a spark plug is loaded with fouling deposits or the electrodes and/or insulator are wet, the voltage rate-of-rise with CDI is actually much quicker than inductive systems using the same coil. This is partly because the power delivery capability with CD ignition is much higher. Recently (as of Oct 2018) I have discovered that CDI provides not only high power, but high power coupled with a leading power factor which is precisely what a spark gap needs prior to breakdown. The spark gap is initially at least, a capacitive load and as such is the preferred current path for power delivered with a leading power factor. This is the main reason why CDI is superior in overcoming shunt resistances such as fouling deposits or wet insulators. An inductive system with its lagging power factor (current lagging voltage) will prefer to drive current through a shunt resistance rather than the spark gap if the shunt resistance value isn't extremely high. Write me if you wish, for a short article describing the experiment that proved this.

Interestingly, the condenser in the Kettering system while initially acting as a load that slows the voltage rise, uses that stored energy by giving it back during, and after spark formation, thus strengthening the spark. With some coils, the contribution of the condenser makes the Kettering system superior in firing fouled spark plugs than if the same coil is switched with a transistor. However, neither points or transistor switch are effective against severe or even moderate spark plug fouling.  

About Voltage Overshoot: It takes voltage and current to initiate a spark. The threshold voltage requirement prior to spark formation is dependent on conditions at the spark plug gap (wider gap requires more voltage as does higher fuel/air density due to compression, and other factors). However, the seldom if ever mentioned fact, is that there is always a voltage overshoot that occurs prior to spark breakdown, and this voltage overshoot varies with ignition systems. Other than conditions at the spark plug gap, the strength of the ignition system also plays a major part in the amount of voltage necessary to initiate breakdown. A weak ignition system may have to produce up to double the voltage of a stronger ignition system to fire spark plugs reliably under all circumstances. This is because it takes both voltage and current (amperage) to create a spark. To sufficiently pre-ionise the spark plug gap takes a particular amount of current that varies with conditions at the spark plug gap. If a weak inductive ignition system is used, the voltage (from self-induction) will rise much higher to provide the required current for this to happen. This explains why some weak ignition systems can degrade insulation much faster than more energetic ignitions. Not only are there more misfires that cause the coil secondary voltage to rise extremely high, even with no misfires the voltage is higher with a weak ignition system. That is, providing the weaker ignition is capable of producing the higher voltage necessary.

         The Winterburn CD ignition operates with a very low voltage overshoot and is able to fire spark plugs in the most adverse conditions because of the high available power. Since a CD ignition produces its voltage differently than an inductive ignition (not from self-induction), the voltage can be regulated to prevent insulation damage. Unfortunately, many high voltage racing CD ignitions do not take advantage of this inherent benefit. Fred Winterburn

About Free Energy: I've had several enquiries about this CD ignition from people attempting to produce systems that extract more energy than the available energy to the system they are designing. There is no such thing as free energy, or over-unity. The energy must come from somewhere. Even when an energy source is available, the energy extraction process is never 100% efficient. For some reason, CD ignition is often associated with false notions of harnessing so called free energy.  F.W.  

If the Ignition is so good, why only a two year warranty? This is a sole proprietorship endeavor and I am not getting any younger. Should I wish to fold the business, I only want to be responsible for warranty repairs for another two years. Rest assured, that the circuit can be easily repaired (even without a schematic) long after company support becomes unavailable. Furthermore, the quality of this CDI makes the chance of requiring warranty repair very unlikely anyway. F.W.  

I haven't been including testimonials on this site, but I particularly liked this one and was given permission to print it here by Martin of Dorchester, (1976 Triumph TR6).
'I gave the old girl a run out yesterday including some fast motoring and the CDI has really made a difference. The engine started without the need for choke, just a blip on the throttle and the engine burst into life.  Previously the car would very occasionally hesitate/falter when accelerating which was sometimes disconcerting when overtaking and I had thought that I might have a fuel blockage at one stage. It would now appear with hindsight  that the likely explanation was probably something to do with the ignition because with the CDI system the acceleration is smooth and swift with no hesitation whatsoever. Very reassuring.'

Some of the cars this CDI has been fitted to: Morgan, Morris, VW, Volvo 1800, Bristol 401, Rolls Royce, Bentley, Daimler, Ford Bronco, Toyota Land Cruiser, Land Rover, 1934 Oldsmobile, Porsche (356,912, Twin plug Carrera) Triumph (TR6,7), MG, Hot rods with Flat head Ford V8s, DKW two stroke, Saab two stroke, Ferrari Dino, Lancia, Fiat Spider, Riley RME, Jaguar Xk140, Mercedes 230SL, Mercedes Gullwing, 1959 Cadillac, NSU, Lotus Elan, Austin Healey, 1961 Alvis, Cord 810,WW2 era Jeeps.