The sound of a 1920s racecar roaring to life is just heavenly

Many car enthusiasts don’t have large shops with access every tool we could reasonably need, but Jay Leno sure does. Like Bruce Wayne, he uses his powers for good, reviving long-forgotten cars and fortunately for us he posts regular updates on his projects so we can all live vicariously through him.

Leno’s latest video update on the restoration status of several projects features six cars currently in various states of repair or modification in the expansive garage. While the first few updates highlight the shop’s ability to fabricate long-unavailable parts (and a few stories of how those particular cars ended up in Leno’s possession), the really interesting stuff is tucked at the end of the video.

There is a monster of a car sitting on a lift, where it has seemingly been for a few years according to past videos. This monster is called the Rabbit 1, and it’s a true English race car that Jay is attempting to civilize so that he may drive it on modern roads. That means a few upgrades to the 1908 Mercedes chassis and the 18.8-liter Benz engine. That gigantic inline-six was originally set up for usage in zeppelins but was repurposed when big power was required on the Brooklands racetrack for 1921.

The engine required new water jackets to be made, which Jay and his crew decided to upgrade from the original steel sleeves to brass, which absolutely makes this engine look the part of a ‘20s racer. With the last of the engine finally buttoned-up, Jay climbs into the driver’s seat and flips the switches to fire the monstrous beast—and boy does it sound mean.

It is fascinating to watch the exposed valve train at work. Interestingly enough, the springs appear to have a conical shape. Traditional valve springs are a cylindrical shape, and only recently have high-performance engines began to return to a conical shape. Much more popular is a “beehive” design which tapers some at the top, but not nearly as pronounced as the conical style. The conical shape allows for more aggressive camshaft lift profiles without spring binding, while still maintaining good valve control.

The car sure looks close to roadworthy and sports a modern clutch and brake in addition to the updated water jackets. Jay closes with a mention to be on the lookout for a video of the Rabbit 1 driving soon. Will he try and beat the cars top speed in 1921 of 113mph? I hope so, if only to hear that engine working hard.