Engine and drivetrain
The 250 Testa Rossa engine was based on Colombo-designed 3.0L V12 used in 250 GT road and racing cars. Carlo Chiti and other Ferrari engineers made several modifications to increase the performance of this already proven engine. The starting point was a 1953-style cylinder block with an overall capacity of 2953 cc, a 73 mm bore and 58.8 mm stroke. Six two-barrel Weber 38 DCN carburetors fed the engine, increased from the 3 carburetors typical for 250 GT engines. The cylinder heads used single overhead cams, 2 valves per cylinder and helical double-coil valve springs (a first for Ferrari).[11][12][13]
The helical valve springs were much smaller than previously used torsion springs, allowing the cylinder heads to be strengthened and secured with 24 studs rather than 18 in previous 250 engines. This increased the overall reliability of the engine by improving head gasket sealing. One spark plug was used per cylinder and the position was changed from earlier 250 designs, now located outside the engine vee between exhaust ports. This allowed for a better spark position and more efficient combustion. Piston connecting rods were now machined from steel billet, rather than forged, which resulted in more stress-resistance at higher RPM.[3] The cam covers were painted bright red, the source of the name "Testa Rossa" (literally, "Red Head"). This tradition and name originated with the 500 TR.[13]
The resulting engine was designated Tipo 128 and generated 300 hp at 7000 rpm. The power/displacement ratio of 100 hp/litre was a particular point of pride for Ferrari, as it demonstrated how Ferrari's engineering prowess could create a competitive engine even under rules restricting displacement. The engineering team improved a well understood, proven design by incorporating new technology and strengthening known weak points. They created an exceptionally durable engine, a massive benefit in endurance racing. Other Ferrari racing cars (250 GTO, 250 P) achieved racing success with the same basic engine well into the 1960s, years after the 250 TR chassis was obsolete.
1957–1958 250 TRs used a 4-speed transmission, followed by a 5-speed transmission in 1959. Customer cars were equipped with a 250 GT-style transmission positioned directly behind the engine, while Scuderia Ferrari team cars sometimes used rear-mounted transaxles for better weight distribution.[13]
Chassis, brakes and suspension
The 250 Testa Rossa used a tubular steel spaceframe chassis, similar to that used in the 500 TR. Compared to the 500 TR, the wheelbase was extended by 10 cm to 2.35 meters. The chassis gained a reputation for durability, as it was designed according to Enzo Ferrari's desire for absolute reliability even at the expense of excess weight.[3][4][11]
All 250 TRs used independent front suspension with coil springs. All customer cars had live rear axles.[4][13] Pre-1960 factory team cars used either live or de Dion rear axles[4][13]
Bodywork and interior
All 250 TRs had 2-seater spider bodies, as did the earlier 4-cylinder Testa Rossas. At the time, this was considered the lightest and most aerodynamic configuration for a racing sports car.
The first 250 Testa Rossa prototype (chassis number 0666TR) debuted at the 1957 Nürburgring 1000km. This hastily prepared prototype was based on a 290 MM chassis and had conventional bodywork by Scaglietti very similar to that of the 4-cylinder 500 TR, except for a large hood bulge.[3][15] For the 1958 250 TR, new bodywork was developed in collaboration between Scaglietti and Chiti with several innovations on the previous 4-cylinder Testa Rossa body. Instead of the conventional fully enclosed front end, the new body had a distinctive cut-away nose reminiscent of a Formula 1 car. The protuberant central air intake was now flanked by deep channels and the headlights were set into nacelle- or pontoon-like fenders that enveloped each front wheel. The purpose of this design was to funnel cooling air inwards towards the brake drums, mitigating the persistent problem of heat-related fade. The lower body was recessed inwards behind the front wheels in order to vent heat from the brakes and exhaust. The front hood was topped with a large bulge and air intake (forward facing on some cars, reverse facing on others) to provide clearance for the vertically oriented carburetors.
Variants and further development
The 250 TR was subject to continual iteration and refinement from 1957 to 1961, resulting in numerous differences between individual cars that may or may not coincide with different chassis production dates. As was common with Ferrari racing cars of the 1950s and 1960s, 250 TRs were frequently modified and updated by the Ferrari factory and/or private owners. Bodywork was often changed to improve performance or to repair crash damage. Ferrari historians track these changes with a numbering suffix based on year of production (such as 250 TR61 for a 1961-style car) as well as descriptors such as "Spider Fantuzzi" to denote cars with bodies fabricated by Fantuzzi. Despite this historiographical systematization, the low-production, hand-built nature of these cars and their use and modification in period mean that differences are most thoroughly explained in the context of an individual chassis' history.
1959: TR59
For the 1959 season, the 250 TR body design was lightly revised by Pinin Farina, with fabrication of the bodies handled by Fantuzzi. The cutaway nose with pontoon fenders was gone, replaced by a more aerodynamic design that still incorporated many ventilation grilles and air inlets.[3][12][14]
1959: TR59
For the 1959 season, the 250 TR body design was lightly revised by Pinin Farina, with fabrication of the bodies handled by Fantuzzi. The cutaway nose with pontoon fenders was gone, replaced by a more aerodynamic design that still incorporated many ventilation grilles and air inlets.[3][12][14]
The 1959 250 TR was the first Ferrari sports car to use disc brakes (manufactured by Dunlop). Disc brakes are much less susceptible to heat build-up and fade than drum brakes, so the extra air cooling provided by the 1958 Scaglietti body was no longer necessary.[3][12][14]
A 5-speed transmission mounted directly behind the engine was also introduced in 1959.
1960: TR60 and TRI60
Dry sump lubrication systems became standard equipment for all 250 TRs in 1960. This allowed the engine to sit lower in the chassis, lowering the car's center of mass for improved handling and enabling a lower, more aerodynamic front profile.[11]
Rear independent suspension was introduced to the 250 TR in 1960. The car equipped with independent suspension was designated the 250 TRI60 (chassis 0780TR) and throughout the season raced alongside the 250 TR60 equipped with a conventional de Dion rear axle.[3][11]
The body of the 250 TR again changed for the 1960 season, primarily due to new regulations requiring a windshield with a vertical height of 25 cm. The new, larger windshield was immediately disliked by drivers, as it was difficult to see over, the plexiglass material could not be effectively cleared by windshield wipers, and the much larger surface area increased drag.[3][11]
1961: TRI61
All 1961 250 Testa Rossas were designated 250 TRI61 as independent rear suspension was now standard.[3]
Due to high drag and visibility problems with the TR60 body style, Ferrari engineers including Giotto Bizzarrini and Carlo Chiti were tasked with completely re-designing the 250 TR bodywork for the 1961 racing season. As a result, the new Fantuzzi-built TRI61 body incorporated a number of dramatic changes, informed by new aerodynamic theories and wind-tunnel testing. The windshield now had a more gradual slope and wrapped around both sides of the cockpit to meet the rear bodywork. Instead of the rounded tail with fairing for the driver's head, the TRI61 had a very high rear body that met the trailing edge of the side windows and tapered to a truncated, slightly concave Kamm tail.[16] This bodystyle was called an "open coupe" and was very similar to bodies used on mid-engined Ferrari sports racers such as the 1961 246 SP.[17]
The front air inlet was now split into two openings, introducing the distinctive "sharknose" or "nostril" style that was also used on other Ferrari sports racing cars such as the 246 SP and the 156 Formula 1 car.[3]
1962: 330 TRI/LM
For the 1962 season, Ferrari developed the final iteration of the front-engined Testa Rossa, the 330 TRI/LM (LM standing for Le Mans). The biggest change from the 250 TR was a Tipo 163 4.0 Litre Colombo V12 developed from the engine of the 400 Superamerica, further improved with Testa Rossa cylinder heads and other modifications seen on 250 TR engines. This engine produced 390 hp at 7500 rpm, significantly more power than the 250-series 3.0L unit. This engine design would be used again in the 1964 330 P.
The single 330 TRI/LM (chassis number 0808) was built from a damaged 250 TRI60 (chassis 0780TR). The original chassis was lengthened and a TRI61-style spider body by Fantuzzi was fitted. At the 1962 24 Hours of Le Mans, this car was driven by Olivier Gendebien and Phil Hill and became the last front-engine car to win an overall victory at Le Mans.[3][20][21]
