Ferrari Lampredi engine
Aurelio Lampredi designed a number of racing engines for Ferrari. He was brought on to hedge the company's bets with a different engine family than the small V12s designed by Gioacchino Colombo. Lampredi went on to design a number of different straight-4, straight-6, and V12 engines through the 1950s, and it was these that would power the company's string of world championships that decade. All were quickly abandoned, however, with the Dino V6 and V8 taking the place of the fours and sixes and evolution of the older Colombo V12 continuing as the company's preeminent V12.
Enzo Ferrari and Lampredi were interested in creating extremely reliable engines for racing use. In 1955, after seeing the success of Lampredi's straight-4 engines, the pair considered a straight-2 engine for the slowest racing courses. Lampredi built a prototype with 4 valves per cylinder and 2493 cc of displacement. It produced 175 hp on the test bench, but broke the crankshaft due to poor balance. The project was shortly abandoned in favor of more-conventional I4 engines.
Lampredi designed a straight-4 engine for Formula Two use. This was later adopted for Formula One and sports car racing cars through the 1950s. The original 2.0 L engine of 1951 would prove to be the longest-lived, continuing through 1957 in various cars.
The initial engine was a 2.0 L (1985 cc) unit with a 90 mm (3.5 in) bore and 78 mm (3.1 in) stroke. This engine was the first Ferrari four-cylinder, appearing in 1951 in the Ferrari 500 F2 entrant in Formula 2. The aluminium engine produced 165 hp (123 kW) with four Weber 45DOE carburettors, with power growing in 1953 to 185 hp (138 kW) with two 50DCOA carbs. It was a high-tech marvel for the time with dual overhead camshafts pushing 2 valves per cylinder and twin-plug ignition.
An entirely different "500" four cylinder appeared in 1953 in the 553 F2 car. This time, bore was 93 mm (3.7 in) and stroke was 73.5 mm (2.9 in) for a total of 1997 cc. Two Weber 52DCOA3 carbs produced 190 hp (142 kW).
The original 1951 Formula 2 engine was resurrected for the World Sportscar Championship in 1953 and the 500 Mondial. With lower compression and two Weber 45DCOA3 carbs, it produced 170 hp (127 kW). The same engine, now at 190 hp (142 kW), was used in the famous 500 TR. The "red head" cylinder head lent its name to the car, the first Testa Rossa. Another TR with this engine, the 1956/1957 500 TRC, was produced for customers to race.
- 90 mm (3.5 in) by 78 mm (3.1 in)
- 93 mm (3.7 in) by 73.5 mm (2.9 in)
- 1953 Ferrari 553 F2
The 500 F2 car was reworked in late 1953 to become Ferrari's 1954 entrant in Formula 1. The engine was bored and stroked to 100 mm (3.9 in) by 79.5 mm (3.1 in) for a total of 2498 cc of displacement. The F1 car, with 13.1:1 compression and two Weber 50DCOA3 carbs, pumped 260 hp (194 kW) from this powerplant. The oversquare 200 F2 engine reappeared again in the 1955 555 F1.
This car would quickly evolve into the 1954 625 F1, though with a much-changed engine. This time, 94 mm (3.7 in) by 90 mm (3.5 in) dimensions were selected, though the total displacement of 2498 cc remained unchanged. Output was now 250 hp (186 kW).
The first application of Lampredi's four-cylinder engine outside Formula 1 and 2 was this same 2.5 L (2498 cc) unit in the 1953 625 TF. The aluminium engine produced 220 hp (164 kW) with 2 Weber 50DCOA3 carburettors. This version was used in the 1953 625 TF. After the Le Mans disaster, the 2.5 L I4 was resurrected for the 1956 625 LM car. Output was rated at 225 hp (168 kW).
- 100 mm (3.9 in) by 79.5 mm (3.1 in)
- 94 mm (3.7 in) by 90 mm (3.5 in)
A big-bore version (102 mm) was also produced. Displacement was now 3.0 L (2942 cc) with 102 mm (4 in) bore, though the 90 mm (3.5 in) stroke was retained. Output nudged up to 225 hp (168 kW) with two Weber 50DCOA carbs.
- 1953 Ferrari 735 S
The bore of the Lampredi I4 was nudged up to 103 mm (4.1 in) for the 3.0 L (2999.62 cc) unit used in the 1954 750 Monza. Dual Weber 58DCOA3 carbs pushed out 250 hp (186 kW).
- 1954 Ferrari 750 Monza
- 1955 Ferrari 857 S
The Type 129 engine was finally raced in the 1956 860 Monza with 280 hp. Bore was the same 102 mm (4.0 in) as the big-bore four, but stroke was now 105 mm (4.1 in) for a total of 3432 cc. These cars placed first and second at Sebring and came second and third at Le Mans that year.
- 1956 Ferrari 860 Monza
For the 1955 735 LM, Lampredi modified the big-bore 1953 I4 into a straight-6. Displacement was 4.4 L (4412 cc) from 102x90 mm cylinders. Triple Weber 50 DCOA/3 carbs pushed out 300 to 350 hp. With this power, the 735 LM could hit 280 km/h on the Mulsanne straight at Le Mans.
A smaller version was used that same year in the 376 S sports car. It used the same 90 mm stroke and 94 mm bore as the original Lampredi Formula One engine and produced 280 hp.
After little luck in Formula 1 with the supercharged Colombo V12, Ferrari moved to natural aspiration. The task of designing an NA V12 for Formula 1 use fell to Aurelio Lampredi, who designed a 3322 cc unit.
Like the Colombos, Lampredi engines found their way into road cars as well. The 1952 342 America and MM were first with big 4102 cc engines producing 200 and 300 hp. Lampredi engines moved to the 250 with the 1953 250 Export. Unlike the earlier engines with their undersquare 80x68 bore and stroke, the 250 used square 68 mm dimensions for 2963 cc total. Power was impressive at 220 hp.