This blog, in addition to the usual maintenance details for classic mini cars, an attempt is made to explain the "whys" and "wherefores" of the various jobs.

Sunday, 11 October 2009

The Ignition Condenser

If the contact-breaker points are badly burned the trouble may be due to too small a gap, which will seriously reduce the life of the points. In most cases, however, it is logical to suspect the con¬denser, which is connected across the contact points in order to absorb the surge of current that builds up in the primary winding of the ignition coil (in addition to the current induced in the high-tension winding), and which, in the absence of a condenser, would cause a destructive arc across the contact-breaker points, instead of the normal slight spark. The condenser also discharges back through the primary windings, causing a more rapid collapse of the magnetic flux and a more intense spark at the sparking plug. It will be obvious, therefore, that an inefficient condenser will not only cause rapid burning of the points but will also result in a weak spark or—if it should short-circuit internally—failure of the plugs to fire at all.

When misfiring and difficult starting are experienced the best test is to substitute a new condenser, or one that is known to be sound. Before finally condemning a condenser make sure that there is no break or short-circuit in the flexible lead connecting it to the contact-breaker terminal post.