Now, what was the situation in Germany after the war? Almost all the production sites were massively destroyed or now lay in the east. After the rubble was cleared, one started building that for which one still had the machines, mainly makeshift trucks and two-wheelers. Only Mercedes reminded themselves of their upper-class origins and firstly, renovated, of all things, the 300. With the exception of the 300 SL, they would be somewhat lagging as far as the general engine development was concerned. Alone the development of Diesel engines would be promoted, the same as by Peugeot in France.
One clear winner arose from the multiple developments of the post-war era, the VW-Beetle. Although it was a pre-war product, suddenly it fit in perfectly. There were a lot of rear-engines around and air-cooling was not as seldom as it is today. After all, it had overhead valves with a bottom-mounted camshaft, pushrods and rocker arms. This would be the case for all utility engines for quite a while, until the cam was moved to the cylinder head, but that would take approx. another 20 years.
Up to the all-deciding energy crisis, there were two important events concerning the combustion engines. The Japanese export began with two-wheelers, then went on to the high revving, but nonetheless durable engines for small cars and provisionally ended up right in the middle of the entire car-market. Then the Wankel (rotary) engine was born, unfortunately the NSU-company was too small. It appeared at first, to be a stroke of genuis, indeed, it had serious disadvantages, e.g., the exhaust-gas problems and the much too high fuel consumption, which, even after many years of developement at Mazda, could not be rectified.
The fact is, that almost all the big manufacturers fell for it, they all took out licences. Whether this was the reason why the NSU-company got into big difficulties or not, cannot be clarified here. Luckily, because at the same time as the crude-oil price-spiral, there was another producer of Diesel motor car engines, Volkswagen. They would establish themselves in the market with reasonably priced, efficient and particularly economic Diesel engines. They would be followed shortly afterwards by Ford, Opel and BMW.
There were actually two crises due to too expensive crude oil, neither of which had a resounding effect on the development of engines. At most, in the USA somewhat smaller engines using European technology were offered, indeed, they couldn't edge the big V-8 engines from the market. The exhaust gas legislation from California however, did have a more lasting effect. It began quite harmlessly with the idling, then, in a relatively short time and with an incredible amount of know-how, swept the entire carburettor technology aside. Inside of a good ten years, with the help of the 3-way catalytic converter, the petrol engine was “clean”. The Diesel did not seem to interest the Americans.