Different grade condensers

You know it. You’ve replaced everything on the car because it doesn’t run cleanly and still it keeps running erratically. This problem is often in the carburettor or ignition. But when those have also been replaced, it becomes a challenge to find the problem. Often, it can then still be that new capacitor that has just not been manufactured properly.

Unfortunately, the condensers are no longer the condensers they used to be. Neither are those from Bosch or Magneti Marelli, which are the best-selling ones for a Fiat 500 and Fiat 126.

After some detective work, we decided to include two other condensors of good quality in our range. Both come from the UK and both are made with care. This results in very good capacitors.

We often hear from customers that price is not so much the issue and that they prefer to pay more for good products. And this is exactly what we stand for, quality over price.

Below is a brief overview of the condensers we sell.

Cheap condensers #

We sell Bosch and Magneti Marelli condensers quite often and usually they are ‘pretty good’. The service life is short in our honest opinion. The capacitance of the condensers is also often outside the specs and thus sometimes throws a spanner in the works.

Midrange condensers #

If you are looking for a good-quality condenser at a fair price, the DD condenser is the one you are looking for.

High-end condensers #

If you are looking for the best in the market, the ShackTune capacitor is the only option. This handmade capacitor meets high standards and is placed near the ignition coil because of the temperature. This condenser is also widely used in rally sport and for good reason.

What is the purpose of the condenser? #

The capacitor (called a condenser up to about 75 years ago) forms a resonant circuit with the inductance of the coil. While the points are closed, current (and the associated magnetic field) builds up in the coil. When the points open, the current is diverted to the capacitor due to the collapse of the magnetic field. The result is a sinusoïdal rise in voltage across the capacitor, which voltage is also across the primary winding of the ignition coil. This produces a large voltage across the secondary (which is connected to the spark plug) igniting the fuel mixture in the cylinder.

The width in time of the voltage pulse is determined by the inductance of the primary of the coil and the capacitance of the “condenser”. The values are chosen for optimal ignition.

If you remove the capacitor, the voltage will try to spike higher but will be limited by arcing at the contacts. But in addition the width of the resulting voltage pulse at the spark plug will be much much shorter and the spark energy much lower. This can result in inefficient ignition (or none at all). Of course, the contact arcing is also undesirable but that’s not the primary reason for the capacitor.

Benefits of a good condenser #

• Less wear on contact points
• Better spark
• Engine runs smoother
• Greater reliability
• Eventually cheaper