Points vs Electronic Ignition on a Classic Car

Written by Petro Olekhnovych, mobile mechanic in Aylesham, Kent

An electronic ignition conversion on a classic car swaps the mechanical contact points and condenser for a sensor and module, usually hidden inside the original distributor. It removes the parts that wear and drift out of adjustment, so the timing stays put for longer. Points still work well if they are kept in good order, so the right choice depends on how you use the car and how much you care about originality.

How points ignition works

Inside the distributor, a cam opens and closes a pair of contacts called the points. They make and break the circuit to the ignition coil. Each time they open, the coil’s magnetic field collapses and produces the spark.

Two settings matter. The gap is how far the points open. The dwell is how long they stay closed. Your workshop manual gives the correct figures for your engine.

Why points drift and wear

Points open and close thousands of times a minute. Moss Motors notes that each opening moves a tiny amount of metal from one contact to the other, unevenly, which slowly closes the gap. The small fibre rubbing block that rides on the cam also wears.

As the gap closes, the timing gradually retards. Typical symptoms are:

• a misfire under hard acceleration, then at steady road speed
• hard starting
• a poor or uneven idle
• burnt or pitted contact faces when you take the cap off

These faults can feel like fuel starvation. So it is worth checking the points before you start pulling the carburettor apart. If the car is running badly on a fresh setup, our guide to carburettor tuning covers the fuel side.

When points are renewed, it is common practice to replace the condenser at the same time.

What an electronic ignition conversion changes

Most conversion kits replace the points and condenser with a magnetic or optical pick-up and a small module. On many kits everything sits inside the distributor, so the engine bay still looks original. Some need only two wires to the coil.

There are two main routes:

• A conversion kit fitted inside your existing distributor. The original distributor, cap and rotor arm stay.
• A complete replacement distributor with electronics built in. Some, like the 123 distributor for Lucas-type units, let you choose between several advance curves.

Either way, you still have a distributor cap, rotor arm and HT leads, and these still need checking and replacing at intervals.

Things to check before you convert

Earth polarity. Some classics are positive earth as standard. Some kits are made for negative earth cars only, while others are sold in positive earth versions. Buy the right one for your car, or for how it has been converted.

Wiring. Fitting instructions for one popular kit warn that connecting the wires wrongly will damage the unit. Identify the live coil terminal before connecting anything.

Timing. After fitting, the ignition timing must be checked and set with the engine running.

The coil. Check the kit maker’s instructions on which coil to use with it, and make sure your existing coil is in good condition.

Originality. If you show the car or want it to stay correct, a hidden kit or simply well maintained points may suit you better than a visibly different distributor.

Points or electronic: which is right for you?

Points suit owners who enjoy tinkering, want full originality, or drive only occasionally and do not mind regular checks. They are simple to diagnose, and a spare set is easy to carry.

Electronic ignition suits cars that are used often or on longer trips, where you want to stop worrying about gap and dwell. It will not turn a tired engine into a fast one. One experienced restorer points out that electronic units are generally reliable but can stop working without warning. Keeping your old points and condenser in the boot as a get-you-home spare is sensible.

Whatever you choose, ignition only works well if the rest of the engine is healthy. Plugs, leads, compression and fuel all play a part. Our classic car servicing in Kent guide explains what we look at.

What affects the cost

There is no single price for a conversion. It depends on whether you choose a kit or a whole new distributor, whether a new coil is needed, and how easy your distributor is to reach. If the timing, cap or rotor also need attention, that adds time. Parts are extra on top of labour.

How we can help

We are a mobile mechanic based in Aylesham and we come to you, at home or at work. We cover Canterbury, Dover, Deal, Sandwich, Folkestone and the villages in between. See all areas we cover.

Classic and vintage car servicing, repair and fault finding are a core part of what we do, including air-cooled VW engines. If your classic is misfiring, hard to start or idling badly, we can find the cause, whether that is the points, the timing or something else.

Labour is £30-£50 per hour, depending on the job and its difficulty. We agree the price with you on WhatsApp before any work starts.

Frequently asked questions

Does electronic ignition make a classic car more powerful?
Not on its own. It keeps the spark consistent and the timing stable, which can help a car that was running badly on worn points.

Can I go back to points after converting?
With a kit fitted inside the original distributor, the old points and condenser can usually be refitted. Keep them, labelled, in case you ever need them.

Will a kit work on my positive earth car?
Only if you buy a positive earth version. Check your car’s polarity and the kit description before ordering.

How do I know if my points are worn?
Misfiring under acceleration, hard starting and a rough idle are common signs. Burnt or pitted contacts confirm it.

Need help? Send a WhatsApp to 07563 350335 with your car’s make and model and we’ll come to you.

Sources

• Moss Motoring: Distributor Breaker Points
• Type2.com: Points, rubbing block wear and timing
• Restore An Old Car: Points vs Electronic Ignition
• JBugs: Distributors, points vs electronic ignition
• MGBits: Electronic Ignition Conversion Kit (Positive Earth)
• MGBits: Powerspark electronic ignition fitting instructions (PDF)
• Moss Motors: 123 Ignition Distributor, Positive Ground, Lucas 25D4/23D4/45D4
• 123 Electronic distributor product notes (Chicagoland MG Club)