Leno’s 1921 Benz Mercedes took a decade to restore, but it was well worth the wait
Jay Leno’s 1921 aero-engined Benz Mercedes, originally built for Brooklands, took the better part of a decade to restore—mostly due to its corroded steel water jackets. This speed machine was originally built using household parts in addition to its 18.8-liter Mercedes engine, which is an inline-six that was rated at 230 horsepower in 1914 when it was used in a fighter plane.
The Benz Mercedes was good for 113 mph in 1921. Leno’s Rabbit-the-First is perhaps less valuable as a collector car than the Chitty Chitty Bang Bangs made legendary by Sir Ian Fleming, but after plenty of work in the garage, the “Rabbit” drives a lot better than most pre-war aero cars.
If you’ve been following Leno’s great restoration updates, you’re familiar with the problem of this Mercedes engine’s water jackets. The Garage’s “metal man” Jimmy had to create new tooling to remake all six jackets out of brass, using silver brazing to end up with a watertight seal all around those massive cylinders.
To ensure a safe “low flying aircraft,” Leno’s experts added a modern twin-plate clutch, new fans, and disc brakes that are still operated by via the lever at the back and the pedals up front. Slightly upgraded Zenith carburetors and a new copper exhaust round out the list of upgrades, while the four-speed gearbox remains the stock Mercedes unit. The engine hasn’t been opened, either, and the chassis is the same heavy, long-wheelbase Benz design from 1908.
This Benz Mercedes Rabbit is from a time before Mercedes-Benz became a thing. With its period generator, rethought valve train lubrication and four valves per cylinder for a redline at 1800 rpm, it looks like an absolute delight. The bossman is famously in love with aero engines, so we imagine this Brooklands special has to be one of Leno’s favorites.