Why Jay Leno Loves Steam-Powered Cars

This article first appeared in Hagerty Drivers Club magazine. Join the club to receive our award-winning magazine and enjoy insider access to automotive events, discounts, roadside assistance, and more.

Two guys called me up a few years ago and said they were going to drive an antique car across America and then write a book about it. They wanted to know if they could stop by the garage and get a picture. I said sure, no problem. Then I asked them what kind of antique car they were driving. The one guy said, "a 1968 Cadillac." A '68 Cadillac!? It just made me laugh because they thought that was an antique car. Maybe I'm the antique, but if you've got air conditioning, an AM/FM radio, power windows, power brakes, and modern tires, are you really putting it all on the line? I ended up writing the forward for the book, and I said, "They are attempting something that Americans did on a regular basis 50 years ago."

I guess that's why I find steam cars so much fun. They're just so different from any car built in the past 70 years, and you are very much a part of the process of keeping them rolling. Heck, it takes a half-hour of setup with some of my steam cars before you can drive them a couple of miles, and I love it at car shows or when German engineers come to the garage and I get to explain how a steam car works, because it's a lost technology and nobody in this day and age has any clue. It's not too often that I'm the smartest guy in the room, but explaining a steam car makes me feel like it.

To start with, a steam car is the exact opposite of an internal-combustion car. For example, in an internal-combustion vehicle, you're trying to get the heat out of it, while in a steam car, you're trying to keep the heat in it. A typical gasoline engine hits about 1200 degrees Fahrenheit at the exhaust ports, while my 1925 Doble E-20 steam car runs at 3000 degrees. We put a temperature probe in it once just to see what it would say. It hit 3000, then the reading started dropping and I thought maybe there was a problem, so we parked it, let it cool off, and pulled the probe out. The brand-new probe had melted, but the 99-year-old car it was installed in continued to run fine.

In a gas car, you combust the fuel internally, inside the cylinder, using the energy instantly to make power. In a steam car, you combust the fuel externally, into a boiler, and hold that energy until you need it. Both types of engines run on thermal expansion, but while the fuel-air mixture in a cylinder expands around 10 times when ignited, a drop of water expands about 2500 times when it turns to superheated steam. Which means you need very little water to make the same power as a gasoline engine.

Every stroke is a power stroke, because steam pushes the piston down, and then a valve opens and steam pushes the piston back up again. So it's not like a four-stroke gasoline engine, which goes 1-2-BANG!-3-4, 1-2-BANG!-3-4. It's just BANG!-BANG!-BANG!-BANG! Except that a steam car doesn't go BANG!, it just goes whoo-whoo-whoo-whoo. Aside from an electric car, a steamer is the quietest form of self-pro-pelled transport you can buy.

And they're quite addictive, too. A two-cylinder 1909 Stanley feels like it's powered by a small V-8, so they're pretty fast for their age and accelerate like a modern car. Except that instead of cruising at 2000 to 3000 rpm as in a gas car, a Stanley cruises at 357 rpm per mile. A Stanley with a body on it that looked like a canoe set a world land-speed record of 128 mph. In 1906!

You certainly have conversations that you would never have if you were driving a '68 Cadillac. I pulled into a gas station once in the Doble with steam coming out of the pressure relief valve. A woman came up and said, "Hey, your car's on fire-it's smoking." And I said no, no, it's steam, so she asked me if it was overheating. I said no, it's a steam car, it runs on steam. She said, "Well then why are you putting gas in it?" I told her gasoline is what you use to heat the water to make the steam. She said, "Then why don't you just park it in the sun?" I said if the L.A. sunshine were hot enough to boil water, we wouldn't be having this discussion. She looked at me like I was crazy.

Maybe I am, but I'm not crazy enough to drive a steam car across the country. If you are driving one across the country, definitely stop by.