1915 HISPANO SUIZA

Experimenting with the best technology at its disposal, Spanish car and aircraft-engine manufacturer Hispano Suiza combined a 1915 chassis with its 8F aero engine, successor to the first V-8 (8A) to attack the sky. Designed by Marc Birkigt, the Swiss-born genius who founded the company, the 18.5-liter, 300-horsepower V-8 is constructed with a pair of assemblies consisting of four cylinders and one head integrated into a single aluminum casting. Steel cylinder liners provide durable wear surfaces. The two cylinder banks are bolted to an aluminum crankcase and the overhead camshafts are gear- and shaft-driven. The sound of its idle is classic V-8 syncopation with little valvetrain noise. The rumble out of each four-inch exhaust pipe is surprisingly polite despite the lack of mufflers.

An Australian mechanic discovered this engine in a burial pit some 40 years ago. He added a four-speed bus transmission and bolted the powertrain into a 1915 Hispano Suiza chassis. Leno bought the concoction in 1989.

This intrepid V-8, manufactured in 21 factories, was the most common World War I liquid-cooled engine found in French and British fighters. By 1946, Hispano Suiza had manufactured over 50,000 aero engines and 12,000 luxury cars. The company made the leap to license-built, turbojet engines after World War II and recently unveiled an electric car called Carmen it hopes to sell in small volumes.

1917 FIAT

Wealthy Argentine racer Adolfo Scandroglio bolted a 21.7-liter, Fiat A.12 inline six into a 1917 Fiat chassis, christening his creation the Botafogo Special after a successful racehorse. Fiat built over 13,000 such engines for nearly two dozen World War I Italian and British biplanes. Advanced features included four valves per cylinder operated by a single overhead camshaft, twin spark plugs, and dry-sump lubrication. It provided 245 horsepower at only 1,700 rpm.

According to Leno, Scandroglio never bothered with a transmission or brakes, instead using a hook to snag the barbed-wire fences that dotted the countryside during his off-road excursions in South America. In 1949, he was killed in a car crash, and the vehicle lay dormant for decades until it was discovered by restoration specialists at Pur Sang Argentina. After the original engine was mated to a fresh Fiat chassis, Leno bought this machine in 2011. Updates include a Lincoln front axle with disc brakes, rear drum brakes, and a four-speed Mercedes-Benz transmission between the mighty Fiat engine and the chain-driven rear wheels.

The “pre-flight” ritual involves hand-oiling the valvetrain’s exposed rocker arms, priming what Leno calls a “toilet-bowl-size” carburetor, and stroking a hand lever operating the fuel pump. The short, two-inch exhaust pipes spit flaming explosions upon start-up. Waves of heat cloud the whole left side of the car. With the current gearing, Leno estimates a top speed of 146 mph, but he acknowledges his courage runs out around 100 mph.

1921 BENZ-MERCEDES

While car builders Daimler and Benz didn’t join forces until 1924, that didn’t stop record chasers from combining components from those two brands in pursuit of speed. In 1921, E.T. Scarisbrick married a 1914 230-horsepower, 18.8-liter Benz aero engine rescued from a crashed fighter aircraft to a 1910 Mercedes chassis, achieving 113 mph at Brooklands, the world’s first banked race track.

Leno acquired this car in 2010 and spent a decade rectifying issues. The inline-six-cylinder, 24-valve engine had integral cast iron cylinders and heads surrounded by sheet steel water jackets prone to corrosion and massive leaks. Replacing the jackets with hand-tooled brass components solved that problem, while adding sufficient luster so that Leno prefers driving this steed minus its hood so all can enjoy the hyperactive valvetrain topping the bright cooling jackets.

New disc brakes were tucked out of sight inside the original drums. Leno’s technicians added electric starting and generating equipment. The original friction dampers and dual chain drives for the rear wheels remain along with the tongue-in-cheek inverted Mercedes star emblem created by artist Peter Helck, who owned this car in the 1960s.

Ample blue smoke accompanies the smooth rumble as it leaves the single, four-inch exhaust pipe. Leno admires this automobile’s surprisingly light steering.

1934 ROLLS-ROYCE MERLIN

The Rolls-Royce Merlin 27-liter V-12 was World War II’s most esteemed piston engine, thanks to its distinguished service in 40 or so British fighters, bombers, and cargo aircraft—including the Hawker Hurricane and Supermarine Spitfire. Packard’s similar license-built V-1650 powered North American’s vaunted P-51. More than 200,000 such engines were built until 1956 with well over 2,000 horsepower achieved with two-stage centrifugal supercharging and intercooling.

Steel-lined aluminum cylinders are topped by heads fitted with twin spark plugs and four valves per cylinder. A seven-main-bearing, forged-steel crankshaft is securely held within a two-piece aluminum crankcase that contains the lubricant, pumps, and filters. Gear-driven single overhead cams open the valves by rocker arms, and two concentric springs close each valve.

A lesson learned during development was that using the thrust provided by aiming the Merlin’s exhaust gases rearward added 10 mph to the Spitfire’s top speed. Unfortunately, the orientation of the exhaust pipes doesn’t accelerate a car on the road.

British engineer Paul Jameson built three Merlin-engined cars in England in the 1970s and 1980s, one of which Leno obtained 30 years ago. Leno’s 1934 Rolls-Royce Phantom II chassis is powered by a 27-liter Merlin from a 1944 de Havilland Mosquito. It lacks prominent Rolls-Royce trappings because the company has a habit of suing those who infringe their trademarks. This car’s only brand identification is on the valve covers and hub caps.

Leno spent several years remaking his Rolls, constructing his own aluminum bodywork, including the wood-accents, the two-seat cockpit, and the distinctive radiator shell. His crew also upgraded the chassis with four-wheel disc brakes, stouter wire wheels, a modern six-speed manual transmission, and a tougher rear axle. Fuel delivery is handled by six Weber two-barrel downdraft carburetors attached to the engine via an intake manifold manufactured in Leno’s shop using a 3D printer. A plate atop one valve cover states, “In memory of Thomas Lane Jr., Corporal US Army, 5th Corps of Engineers Special Brigade, died Normandy Beach June 6, 1944.” That somber tribute is for a close friend of Leno’s who was only two months old when his father perished in World War II.

Weighing 4,800 pounds, this Rolls boasts 60 gallons of fuel capacity and nine gallons of oil sustaining its estimated 1,000 horsepower, but it loafs along at 80 mph with the engine turning only 750 rpm with the six-speed transmission in top gear. An unusual hand-cranked, starting magneto delivers a shower of sparks to help the engine fire during start-up. This car has two batteries in series to provide the 24 volts required by the V-12 for cranking and running; one of the batteries supplies 12 volts to the lights and accessories.

1930 BENTLEY METEOR

Merlin engines deemed unsuitable for flight were stripped of their supercharger, renamed Meteor, and assigned to battle tank service. British constructor Bob Petersen married one such 27-liter V-12 to a 1930 Rolls-Royce Phantom II chassis. A contemporary Bentley supplied the cowl structure, steering, brakes, and radiator. Petersen’s custom four-seat coachwork consists of hardwood body framing covered with padded leather exterior surfaces.

Modern touches include electronic fuel injection, a U.S.-made Allison automatic transmission, disc brakes secreted inside period Bentley drums, power steering, and turn signals. The finished car weighs about 6,000 pounds and has 650 to 700 horsepower, according to Leno.

On the road, this V-12 spins at only 1,100 rpm with the car cruising at 60 mph. Even though it lacks the poise of its Merlin-powered garage mate, Leno says it’s “like flying an airplane.”

2012 ECOJET

Leno recently constructed a turboshaft-powered sports car in his shop from scratch with the help of a few prominent benefactors. The Eco part of this car’s name is a nod to environmental consciousness: It runs on a biodiesel fuel sourced from soybeans, and the cockpit is upholstered with Alcantara faux suede material in lieu of leather.

GM’s design department contributed the exterior shape employing themes from the stillborn Cadillac XLR spinoff of the 2020 Corvette. Like the new ’Vette, the EcoJet has a mid-engine layout with the powerplant positioned just behind the compact two-seat cockpit accessed by diagonally hinged doors. Metalcrafters molded the body panels in carbon fiber, hoping to keep curb weight well below 3,000 pounds. The 650-horsepower Honeywell LTS101 helicopter engine—which, over the years, has powered the Bell 222, the Airbus BK117 and AS350, and the Avicopter AC311—is mounted atop a Corvette four-speed automatic transaxle that powers the rear wheels through an 8:1 gear reduction unit to drop the turbine’s high rpm to a piston engine’s range of operation.

An Alcoa-built aluminum spaceframe fitted with Corvette suspension components serves as EcoJet’s chassis. To provide sufficient stopping power, huge Brembo carbon-ceramic rotors—each squeezed by six-piston calipers harvested from the front of a Corvette ZR1—are used at all four corners. Alcoa also crafted special 20- and 22-inch forged aluminum wheels with a special Dura-Bright surface that never requires polishing.

The turbine’s exhaust exits through two high-mounted rear outlets. Since this engine delivers 200 horsepower at idle, the brakes must be applied below 60 mph. Fuel consumption at 70 mph is a horrendous five mpg. Thus far EcoJet has won its only drag race versus a Learjet on a local runway.