The gradual development of the ignition is only one part of the whole developing progress concerning the engine. More performance with a lower fuel consumption was required, particularly then, when it was not being called up. This seems to call, e.g., for a raising of the compression, strictly combined with the development of higher octane fuels.
The carburettor technology led the way. Until the introduction of the Lambda-regulation, in the partial-load area it functions with a lean mixture, only when full-load is reached does it substantially enrich the mixture. Apart from a higher compression it also makes higher demands on the ignition system. Moreover, one should not forget that the ignition system was, for a long time, the most sensitive area of the combustion engine.
Apart from moisture, another aspect threatens the ignition system as well. Namely, it should have a relatively reasonable price. This concerns above all, the equipment in smaller motor vehicles where the price calculation is cut to the minimum anyhow. One weak spot, at this time, was starting behaviour, whereby, the starter motor of the battery ignition draws the necessary current. Thus, we arrive at the curious results of tests where, e.g., it can be proved that certain small cars simply cannot be started at temperatures of -25°C.
In the beginning, also due to the frequent oil changes, it wasn't noticed just how much servicing the battery ignition needed. Replacing the contact-breaker points and re-adjusting the ignition every 2.500 kms was perhaps, shortly after 1960, still affordable at VW, but with the wages climbing and, e.g., with foreign cars like Alfa Romeo, it started to get really expensive.
Not only the mechanical wear and tear of the contact-sliders compared with the cam, but also the static dwell-angle was a disadvantage. For the even charging of the ignition coil it should have had a much smaller angle for idling than for maximum RPM, because then the angle is passed much quicker. This could only be brought about by the later appearing electronics.
The last thing that the conventional battery ignition can still manage without the help of electronics, is the inclusion of the engine load. This was introduced in 1936 and for a long time, would be the last highlight in the development of the ignition system. Whereby, one should not forget the retard chamber which was introduced after 1970 to conform with environmental requirements. We can assume, that from 1935 to 1986, the ignition system remained very much unchanged. 05/12