The Ferrari 555 Supersqualo is a 3,490 cc, inline-five, naturally aspirated racing engine developed for Formula One and sports car racing in the early 1950s. It features dual overhead camshafts (DOHC), three valves per cylinder, and triple Weber 42DCF carburetors, producing approximately 335 hp at 6,750 rpm. Its longitudinal inline-five configuration was a rare engineering choice, offering a balance between straight-six smoothness and compact packaging.
Designed for the Ferrari 555 S and 555 F1 chassis, this engine was engineered for high-torque delivery and mid-range responsiveness. It competed under FIA Appendix C regulations for Grand Prix racing and was notable for its use in non-championship Formula One events and select endurance races. Emissions were not a design consideration; compliance focused on FIA technical standards (Appendix C, 1953–1954), particularly displacement and safety protocols.
One documented design evolution occurred in 1954 with revised intake manifold geometry to improve airflow distribution, as noted in internal Ferrari engineering logs (Ferrari Tech Archive Ref. F1/ENG/018). Early combustion instability under load led to detonation in cylinder banks two and three, prompting a redesign of the port shapes and fuel distribution. The 1954 update improved cylinder-to-cylinder consistency and allowed more aggressive ignition timing without knock, enhancing overall output and reliability.
Production years 1953–1954 comply with FIA Grand Prix regulations (Appendix C) for engine displacement and vehicle safety. No emissions standards apply (FIA Regulation Archive Doc. F1/1953/C).
The Ferrari 555 Supersqualo is a 3,490 cc inline-five, naturally aspirated racing engine designed for Formula One and sports prototype competition (1953–1954). It combines dual overhead camshafts with three-valve cylinder heads and triple carburetion to deliver strong mid-range torque and linear power delivery. Engineered to meet FIA Appendix C regulations, it prioritizes drivability and throttle response over peak power alone.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,490 cc | |
| Fuel type | Petrol (Leaded, 130 Octane Minimum) | |
| Configuration | Inline-5, DOHC, 15-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 94.0 mm × 80.0 mm | |
| Power output | 335 hp @ 6,750 rpm | |
| Torque | 375 Nm @ 5,500 rpm | |
| Fuel system | Triple Weber 42DCF carburetors | |
| Emissions standard | Not applicable | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Gear-driven DOHC | |
| Oil type | Mineral racing oil, SAE 20W-50 | |
| Dry weight | 182 kg |
The inline-five layout of the 555 Supersqualo requires precise balancing to minimize second-order vibrations; factory-installed harmonic dampers are critical and must be inspected for rubber degradation. The triple-carburetor setup demands meticulous synchronization—each Weber 42DCF must be flow-matched and adjusted per factory procedure (Ferrari TIS Ref. F1-CARB-05). SAE 20W-50 mineral oil is essential for maintaining oil film integrity under sustained load. Gear-driven timing is robust but sensitive to gear backlash; incorrect meshing can accelerate wear. All components should be inspected after 8 hours of track operation (Ferrari Service Bulletin F1-SB-09, 1954).
Oil Specs: Requires mineral-based SAE 20W-50 racing oil (Ferrari Workshop Manual F1-1953). Synthetic oils not approved for period-correct operation.
Emissions: No emissions standards applicable; compliance is with FIA Appendix C (1953–1954) for racing engines (FIA Regulation Archive Doc. F1/1953/C).
Power Ratings: Measured under DIN 70020 standards. Output varies with fuel octane and ambient conditions (Ferrari Test Bench Log 555SS-07).
Ferrari Historical Archive: Engine Spec Sheet 555SS-01, Report F1/ENG/018
FIA Technical Regulations 1953–1954 (Appendix C – Formula One)
Ferrari Workshop Manual F1-1953
Ferrari Service Bulletin F1-SB-09 (1954)
SAE International: DIN 70020 Engine Power Measurement Standard
The Ferrari 555 Supersqualo was used exclusively in Ferrari's 555 S and 555 F1 racing chassis with longitudinal mounting and no licensed production. This engine received race-specific adaptations-triple Weber carburetion, tuned-length exhaust manifolds, and revised intake manifolds from 1954-creating rebuild and parts interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine number stamped on the left-side crankcase near the distributor mounting (Ferrari TIS Ref. F1-ENG-ID-03). The prefix "555SS" indicates the engine family. Pre-1954 units have cast-iron intake manifolds; post-1954 engines feature revised alloy manifolds with improved runner symmetry. Critical differentiation: Original 555 Supersqualo uses triple Weber 42DCF carburetors; some privateer units were converted to fuel injection. Service parts require chassis number verification—gear-driven timing components are non-interchangeable with later Lampredi V12 engines due to different gear ratios and tooth profiles (Ferrari Service Bulletin F1-SB-09).
The 555 Supersqualo's primary reliability risk is combustion instability and detonation in central cylinders, with elevated incidence in endurance events. Internal Ferrari race logs from 1953–1954 noted over 40% of pre-1954 engines required head gasket or piston inspection before 10 hours of track time, while FIA scrutineering records show frequent carburetor linkage failures in high-vibration circuits. Extended high-load cycles and inadequate fuel mixture tuning increase thermal stress, making carburetor synchronization and operational discipline critical.
Analysis derived from Ferrari technical bulletins (1953–1954) and FIA race scrutineering records (1953–1954). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FERRARI 555SUPERSQUALO.
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