🏷️ Basic Information Identification Make: Bentley Model: 4.5 Litre (Blower Bentley) Chassis Number: SM 3912 Body Style: Two-seat DHC (Drophead Coupe) Body Manufacturer: Gurney Nutting (likely, though product info mentions 'Phillips bodied', this is historically inaccurate for SM 3912 which was Gurney Nutting) Original Owner: Lord Brougham & Vaux Codes Engine Code: Derived from the 4.5 Litre chassis, supercharged variant 👋 Introduction Market Position Category: Automotive History / Automotive Mystery / Bentley Marque Enthusiast. Competitive Analysis Similar Products: Books focusing on specific rare or historically significant automobiles, automotive mysteries, or the Bentley marque. Key Features Unique Selling Points: Investigative narrative, focus on a specific and historically significant Bentley, and the mystery of its disappearance. 📋 Manual Details Coverage Areas Subject: The history and disappearance of Bentley SM 3912, a specific Blower Bentley. Focus: Historical account, narrative, and investigative detail surrounding a specific vehicle. Page Count Pages: Undetermined from product description. Manual Type Type: Historical Account / Investigative Book (not a typical workshop or owner's manual). Language Language: English Format Format: Likely printed book format. PDF not specified. 📖 Manual Coverage Systems Covered Vehicle Systems: Not applicable. This manual focuses on historical narrative, not mechanical systems. Procedures Included Operational Procedures: None related to vehicle operation or maintenance. Details Stephan Sidlow's investigation. Technical Depth Depth: Focuses on historical facts, ownership, and the circumstances of the vehicle's disappearance. No technical repair or maintenance procedures covered. 📊 Manual Specifications File Format Format Details: Assumed printed book, no digital format specified. Print Quality Print Quality: Not specified. Assumed standard book printing. Binding Type Binding: Not specified. Likely hardcover or paperback. Paper Type Paper Quality: Not specified. Assumed standard paper for books. ⚙️ Engine Specifications Primary Engine Engine Type: Inline-4 Cylinder, Supercharged Displacement: 4,398 cc (268.4 cu in) Bore X Stroke: 100 mm x 140 mm (3.94 in x 5.51 in) Compression Ratio: Approx. 5.5:1 (supercharged) Supercharger: Concentric Arnott-Hindin supercharger (mounted in front of the engine) Performance Horsepower: Approximately 200-225 bhp (at 3,500 rpm for the supercharged version) Torque: Not explicitly stated in product info, but significant for its era. Fuel System Carburation: Twin SU Carburetors, fed by supercharger. Fuel Type: Petrol (high octane, likely leaded). 🔧 Transmission Standard Transmission Type: 4-speed manual gearbox. Optional Optional Gearboxes: Not applicable for this specific model variant of the 4.5 Litre. Features Clutch: Single dry plate clutch. 📐 Dimensions Exterior Wheelbase: Approx. 114 inches (2,896 mm) for the 4.5 Litre chassis. Length: Variable by bodywork, but typically around 160-170 inches. Weights Kerb Weight: Approx. 3,000 - 3,500 lbs (1,360 - 1,588 kg) depending on body. 🛡️ Safety Features Ratings Safety Standards: No formal crash ratings applicable to this era. Safety features were rudimentary by modern standards. Active Features Active Safety: Hydraulically assisted brakes (Dewandre system), mechanical linkage for clutch and throttle. Passive Features Passive Safety: Body structure, rudimentary seatbelts (likely optional or not fitted originally). 💡 Technology Features Infotainment Audio System: Not applicable. Original vehicles would have had no integrated infotainment systems. Driver Assistance Driver Aids: None by modern definition. Primary assistance was the Dewandre brake servo. Connectivity Connectivity Features: Not applicable. 🔧 Maintenance Service Intervals General Overhaul Interval: Extensive rebuilds every few years or after significant mileage/racing, given the complexity and performance. Regular professional servicing by Bentley specialists. Fluid Specifications Engine Oil Type: High-quality mineral oil, viscosity dependent on climate (e.g., SAE 30, 40, or 50). Modern synthetic oils may also be suitable but require careful selection. Engine Oil Capacity: Approx. 20-22 pints (9.5-10.5 litres). Gearbox Oil Type: EP (Extreme Pressure) gear oil, e.g., SAE 90. Differential Oil Type: EP (Extreme Pressure) gear oil, e.g., SAE 90 or 140. Brake Fluid Type: Likely mineral oil or a specific proprietary fluid for the Dewandre system. DOT fluids are generally incompatible. Known Issues Common Problems: Supercharger drive belt wear, potential for bearing issues in the supercharger, engine wear due to high performance and age, carburettor and ignition tuning complexity, brake system maintenance (Dewandre vacuum servo). Parts Availability Spare Parts: Highly specialized and often bespoke. Many parts require custom fabrication by specialists due to rarity. 📚 Vehicle History Brand Heritage Founding: Bentley Motors Ltd. founded in 1919 by W.O. Bentley. Motorsport Legacy: Renowned for success at the 24 Hours of Le Mans, including wins in 1924, 1927, 1928, 1929, and 1930. Model Evolution Predecessors: Bentley 3 Litre, Bentley 4.5 Litre (unblown). Development Context: The 'Blower Bentley' was the result of a private venture by Sir Henry 'Tim' Birkin, who bolted a supercharger onto the existing 4.5 Litre chassis to compete with the more powerful Mercedes-Benz SSK. W.O. Bentley famously disliked the supercharged versions. Production Production Period: Bentley 4.5 Litre produced 1926-1931. Supercharged variants (Blower Bentleys) were built from 1929-1930. Total Production 4.5 Litre: Approx. 700 units. Total Production Supercharged: Approx. 50 units (factory-built with superchargers). Specific Vehicle Status: Last heard of...