With 18,200 Aurelia made, one would think production was standardized - but it was not. Rather the Aurelia was a car in steady evolution. Motors, transmissions, rear suspensions, and body lines were changed regularly for each of the models, in Lancia's pursuit of perfection, regardless of the cost. Above are Ettore Zaccone Mina, Bosco and Falleo, designers of engines, drivetrain, and chassis, respectively, doing what they did best: still designing.
Aesthetic changes in the cars are relatively well documented, and the real story is the mechanical evolution in both the sedans and the coupes, with a large number of changes in just a few years. How could they make so many, everything in the cars, and yet maintain the quality that they had? Each Aurelia felt like it was made specially for its particular purpose regardless of whether it was a sedan, a GT coupe, or an open car. Gear ratios, spring rates, engine tune, fittings, instruments, brakes, all were changed for each model and sub-model. How was this done?
Lancia's production model was an unusual one. It was noted as early as the 1920s as a form of "industrialized craftsmanship", between a mass production model on one hand, and hand-crafted, small production efforts on the other, In essence, Aurelias were both mass produced and niche marketed – constantly improved and revised over their lifespan. The range of these changes are many; understanding why and how they were done is part of the charm of these cars.
The first Berlina motors are 1754cc, increased one year later to 1991cc. The second series Berlina ( B12) motor was upsized to 2261 cc. In the B20 coupes, they began by using the Berlina’s 1991 cc motor in the first B20 coupe, but changed the carburetion from one to two single barrel carbs to achieve 75 hp. In the 2nd series coupe (1952), new heads had revised valve orientation for better breathing, a design that was used for all the later B20’s, but not for berlinas.
The 3rdseries B20 began use of the 2.5 liter engine, common for all the later B20s and B24s. The 4th series engine is basically the same, save a change to shell bearings. The 5th and 6th engines have only valve train improvements, and oh yes, a different camshaft.
In summary, from 1950-1954, Lancia increased the Aurelia engine size three times, makes two head configurations (parallel and skewed), four different capacities (1754, 1991, 2261, 2451 cc), and some 7 different block castings! Along with this were several different carburetion setups - a single barrel,a double use of single barrels, a Solex two barrel, and a Weber single two barrel for the later engines.
The most detailed explanation of the different models and variation was prepared by Bill Stebbins, an engineer and Lancia man of the highest caliber. His remarkable 1982 sketch outlined all the major changes in the different Aurelia models: