D cars included a range: D20, D23, D24, D25 and D50. The development sequence is a bit odd: it started with the D20 coupe. This was then changed to an open car by lopping off its top, and became the D23. The D24 was yet another development, with its success in 1953-54. The D50 was introduced in 1954, and developed further in 1955, with much promise, before it was handed over to Ferrari in the summer of 1955. The D25 was started in 1954 (check) and run in 1955 but was not active much.
This page is about the development of the D20, that is the passage from the Aurelia racing coupes to their first sports racing car. The B20 had taken a major step to being a competition car with the Corsa built in 1952 as a similar car to the s.2 B20. No corsa remain, and so determining the exact relationship of the cars to the standard B20 is difficult, but it appears to have used the s.2 running gear, with the new heads featuring the angled valves. The body was aluminum, the windows Perspex, and the interior stripped out to racing functionality. The transition to the D20 will be examined in three different ways: the engine, the chassis and suspension, and the people involved.
Engine: the D20 engine is a DOHC 60 degree V6 engine. It is essentially a development of the Aurelia block, but is totally different - with differing stud locations, etc. However, its central elements (crankshaft, bearing spacing, bearing sizes) are the same as the B20. The bearing size is identical to that used in the s.XX B20, but more importantly, the crankshaft web spacing, and basic layout is the same - the D20 simply had more counterweight on the webs - as can be seen by this drawing, with additional volumes for the D20 crankshaft shown in purple (D20 info from a drawing of that crankshaft, B20 info from a B20 s.2 crankshaft).
The first engine for the sports racing cars was the B110, with drawings started in May/June of 1952 by Zaccone Mina, with De Virgilio upon his return from Le Mans that summer. The B110 is a 2.5 liter motor, and p
From the book: Gianni Lancia’s 1952 commitment to competition started the development of a series of overhead- cam motors, which De Virgilio called bialbero. The first was the B110, a double-overhead cam V6 motor of 2.5 liters (80.5 x 81.5mm). Its design was started in March 1952 by De Virgilio’s assistant, Ettore Zaccone Mina, who was working directly under Jano while De Virgilio was away with the racing Aurelias. Returning from Le Mans in June, De Virgilio joined the in-progress work, initially sketching an overall geometry for the B110 motor and sizing its connecting rods. In July he outlined how to assemble and time its camshafts. Zaccone spent three days at Moto Guzzi, the leading motorcycle company, to study its use of needle bearings, which were used for the connecting rods in the B110 motor, which was running on the test bench by October. Its intake valves were 44mm (exhausts 40mm) and compression ratio was 8.5:1.
Zaccone proudly affixed his name to the B110 drawings (as he did for all the D motors), although careful inspection indicates this was done after the fact. While parentage of the B110 was Zaccone’s, De Virgilio prepared a layout sketch for the motor early in its design on July 3, 1952, and in October made notes about changes to its valve lift. Also, De Virgilio kept in his files a handwritten B110 motor test from March 1954, and listed its specifications in detail. No other tests of the B110 were found in the Archive.
site design and content copyright G. Goldberg, images as noted Proudly powered by Weebly