What is a distributor… What does it do in my classic car?

A distributor is the key part of a classic car ignition system, tasked with controlling the output of the ignition coil and sending the spark to the relevant cylinder.

Going into more detail, a distributor works in conjunction with the coil to perform two functions:

1. It makes and breaks the low voltage or LT circuit of the coil at precise timing to generate the high voltage within the coil.
2. It distributes the high voltage, or HT energy from the coil to the appropriate spark plug via the distributor cap and rotor arm.

The critical function of the distributor is to control the advance (or the ignition advance) whereby the spark occurs earlier as the engine speed or load increases. This is achieved via centrifugal forces acting on springs and weights within the distributor body, or the vacuum generated by the carburettor, or a combination of the two. The distributor position needs to be carefully set so that the correct spark timing is obtained. The distributor needs regular maintenance to ensure that the points gap and dwell angle remain correct. Typically the contact breaker points need to be adjusted or replaced every six to twelve months. A Powerspark ignition electronic conversion kit replaces the points with a magnetically triggered electronic circuit, using less moving parts and eliminating tedious maintenance.

Our kits are easy to fit at home, are fit and forget and are available for a very wide range of cars in both positive and negative earth.

Points and Condenser classic car ignition… What is it and how does it work?

How does a points and condenser ignition system work, and what are the pitfalls?

The points are a mechanical switch which are opened and closed by a cam on the distributor shaft.

When closed, the circuit is complete and the coil becomes energised. When the points open, the circuit breaks causing the energy to be released from the coil, creating the spark. The condenser reduces arcing across the contact points, helping the points to last longer.

At a cruising speed of 2,500 rpm, with a four cylinder engine, the points will be opening and closing more than 83 times per second, or 5,000 times per minute. That could be 30 million sparks in 6,000 miles. Although they are made from a tungsten alloy, it’s no wonder that the points need maintenance. At regular intervals the the maximum gap of the open points needs to be measured and adjusted if necessary. If the gap between the points becomes too small, the coil will be energised for too long and will overheat. If the gap is too large, the coil will not be fully energised between each cycle resulting in a weak spark. Eventually pitting on the contacts themselves and wear on the rubbing block mean that the contact breaker set will need replacing, usually after about 6,000 miles.

What is electronic ignition… do I need it in my classic car?

How do you convert a classic car to electronic ignition? Electronic ignition explained

A Powerspark Electronic Ignition Kit replaces the mechanical points and condenser inside your distributor with a magnetically triggered ignition module.

Contact breaker points make and break an electrical circuit by opening and closing a mechanical switch. A Powerspark electronic ignition kit does away with these moving parts, instead replacing them with a magnetically triggered electronic ignition module. While conventional points need replacing and the timing adjusted after approx 6,000 miles, our electric ignition kits are fit and forget – there are no moving parts giving it a much longer life than a points set, and once set the timing will never need adjusting again.

With a points system, setting the points gap sets the dwell to a specific angle – dwell is the period that the points are closed, thus energising the coil. With a fixed dwell angle, the coil is energised for too long at low RPM, and insufficiently at high RPM. Our electronic ignition systems feature automatic intelligent dwell, so that the coil saturdaration is always optimised. From the 1980s onwards, car manufacturers adopted electronic ignition as standard, resulting in cars that were more reliable and required less maintenance. A powerspark electronic ignition kit provides the advantages of modern technology with minimal changes to your classic car. Without removiing the distributor cap it is virtually impossible to spot the upgrade.

What is an ignition coil… What does it do in my classic car?

An ignition coil is a small metal canister containing two windings of wire around an iron core, that generates the electricity that’s required to produce a spark.

The ignition coil is the powerplant of your ignition system, and should be checked regularly as part of your ongoing maintenance. Traditional coils feature two metal rods, wrapped with copper wiring and immersed in oil, inside a metal canister. The oil is there to insulate the windings and keep them cool, however these are prone to leaking and overheating. Modern ignition coils are set in resin, making them ideal to be mounted on any angle. The ignition coil was present on most cars up until the 1990s, when coil packs and more complex ignition systems began to take over.

When the points close, the current flows through the primary windings inside the coil creating an electro magnetic field. When the points open, this field collapses creating a high voltage in the secondary winding, which finds it’s way from the ignition coil to earth via the rotor arm, distributor cap, HT lead and then spark plug, generating a spark at the critical moment. Modern systems that don’t have a distributor will use multiple coils, either one per plug or one shared between a pair of plugs. At Powerspark we offer a range of ignition coils, all of which are tried and tested products that we stand behind. Our range includes the well known names of Lucas, Bosch and Viper, as well as our own Powerspark coils, products that have been carefully chosen by our team of experts.

What are HT leads… What do they do in my classic car?

What are HT leads, what do they do and why are they important in my car?

HT leads, or High tension leads, high tension cables or ignition leads, connect the ignition coil, distributor and spark plug. They need to be high quality, and capable of withstanding high temperatures.

The ignition coil first transfers the electrical spark energy to the distributor cap, which via the spinning rotor arm, travels down to the HT leads to the spark plug. Traditionally, ignition leads would have been made of a copper core tightly wrapped with a cotton braid, however modern performance HT leads are more likely to be made of silicone with a carbon core.

Our HT leads have a carbon ferroflex core, connected to a brass terminal via a conductive brass spike. This makes for a strong, flexible and durable lead. Many of our HT lead sets are available to buy off the shelf, however we also custom make HT lead sets for a wide range of automotive applications. If your car uses electronic ignition, you’ll need modern HT leads as copper leads will break down the ignition module, causing it to fail. Your HT leads are classed as a consumable, however our modern HT leads have a very long life cycle. Always check your HT leads as part of your general maintenance checks.

What is a trickle charger… What does it do for my classic car?

What is a trickle charger and what should I look for when buying one?

A trickle charger is designed to charge your battery at a low current, which takes a little longer than a fast charger, but will keep your battery good health for longer. A good trickle charger will take care of your battery, keep it topped up and switch off when necessary. They are perfect for rarely used vehicles, boats or motorhomes.

Any battery will drain if left unused for a period of time, more so with electrically complex vehicles such as motorhomes. A good modern ‘smart’ trickle charger will intelligently read the battery status and go through a series of charging stages to optimise battery condition and keep it charged and ready for use. An intelligent trickle charger can be left permanently connected whilst a vehicle is in storage, These are easy to use products that plug into the domestic mains supply and connect to the battery with a clip connection for each of the battery terminals.

Unlike a ‘dumb’ charger that will contiue to push voltage into a fully charged battery, a smart charger such as our B6001 is programmed with multiple automated steps to prepare the battery to accept a full charge. A typical smart charger can have up to 8 or 9 distinct steps to get the best performance from a battery.

They usually start with a ‘desulphation’ step that attempts to counteract the effects of a deeply discharged and neglected battery.
This will be followed by a high current phase that gets most of the charging done, before a ‘bulk’ charging phase optimises voltage but allows the current to drop which brings the battery up to near full charge. Once the battery is fully charged, a maintenance phase periodically monitors the battery condition and tops up the charge as necessary.

How to fit a Positive Earth Powerspark electronic ignition kit:

How to fit a Positive Powerspark electronic ignition kit:

These instructions are for our positive earth ignition kits only. See separate post for negative earth.

Before you begin, it’s a good idea to disconnect the car battery. Most Powerspark® kits can be fitted to the distributor while still in the car. If you choose to remove the distributor, turn the engine to Top Dead Centre and mark the distributor / rotor position carefully.

Remove the distributor cap, rotor arm, contact points and condenser carefully, retaining the screws and withdraw the wires through the distributor body.


Test fit the module first and then apply a small amount of the white thermal grease provided (2 or 3 small blobs is sufficient) to the underside of the module baseplate, leave the screws fitted. Some kits are pre-fitted to a complete baseplate, in which case the thermal grease is not required.

Check there is sufficient slack in the wires inside the distributor body for the base plate to turn when a vacuum unit is fitted, inserting the rubber grommet or plastic plug to prevent the wires from chaffing. Secure the wires in the distributor body using the supplied cable tie to keep these out of the way of moving parts.

Fit the new trigger ring pressing down gently onto the shaft. Some kits have more than one trigger ring, use the one that fits best. On occasion the ring can be tight and may need to be carefully sanded to make it wider. Only do this to make minor alterations.

Fit the rotor arm and rotate the spindle to check there is clearance between the module and the trigger, and that the rotor arm does not foul the module.

The kit will find it’s own position but if the ring and kit touch then move the module to achieve a close but not touching position (3 or 4 mm maximum).

Locate the live feed from the ignition switch to the coil and disconnect it from the coil. Connect this wire to the the WHITE wire from the Powerspark® kit.

Connect the BLACK wire from the Powerspark® kit to to the coil() terminal (sometimes labelled ‘1‘) ensuring no other wire is on that same side.

Make up a new wire to connect the coil(+) to earth or ground. The coil mounting bracket is often a good location for this.

Failure to connect the wires correctly may result in damage to the Powerspark module. Never connect 12v directly to the black wire.

Refit the distributor cap, start the engine. Check and adjust the dynamic timing for best running.


If you can’t get the ignition to work once installed, try these suggestions:

  • Check the coil resistance prior to fitting this unit to ensure that your coil has a resistance of more than 1.5 ohms.
  • Check that the ignition feed from the ignition switch is not connected to the coil.
  • The Black wire must be connected to the coil(-) or ‘1’.
  • Check that the coil(+) terminal is connected to a good earth. 
  • For testing purposes, no other wires should be attached to the coil terminals, except for the centre HT lead to the distributor cap.
  • Check the condition of the cap and rotor arm (replacing them if possible for testing).
  • Do not connect coil(-) to earth.

Classic Cars you should buy: This 1966 Aston Martin DB6 Vantage Shooting Brake

An occasional blog series where we find cars from around the internet and try to persuade you to buy them… 

What is it?

It’s an Aston Martin DB6 Estate Car, of course! Forget the Volvo 240 Torslanda, this is the wagon you want for your winter weeks away.

Errr, what?

Traditional coachbuilders Harold Radford & Co converted 12 of these Aston Martin’s to ‘Shooting Brake’ spec, with 8 in Right Hand Drive and 4 in Left Hand Drive. This one was built NEW as a station wagon, complete with roof rack. It’s done 50,000 original miles and is simply beautiful.

Where did you find it?

For sale with Bonhams Auctions, as part of their August 14th sale. It’s estimate at £ 760,000 – 910,000.

Why buy it?

First of all, to go surfing. Secondly, because it’s super cool, highly exclusive and very unusual. Wouldn’t it just look great with a longboard on the roof at Woolacombe or Croyde Bay? We like the idea and the very antithesis of the utterly preposterous expense of a car with a surfboard on top.

How much is it?

It’s estimated at three-quarters of a million pounds, to a bit under a million, giving quite a large window.

The £150,000 ‘leeway’ in the middle just goes to show that even Bonhams aren’t too sure where the hammer will fall on this car.

Is that a lot?

Who knows? You can’t buy another one.

If you want a DB5 you’ll need somewhere between £600,000 and £900,000 depending on which way the wind is blowing, and a DB6 comes in just a snip less.
An estate, though? We shall find out, and blog about it.

But can I fit Powerspark Electronic Ignition?

Yes of course you can! We’ve done extensive research on this for customers in the past, and our ‘D12 or D62H’ high energy distributor is the one for the job.

This is a Lucas 25D6 based distributor, not too dissimilar to the type used by the Austin Healey.

More photos of the 1966 Aston Martin DB6 Vantage Shooting Brake: