I Found Smokey Yunick’s Legendary Hot Vapor Horizon Car on eBay
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I’ve been a fan of Smokey Yunick and his hot vapor engine ever since I read about it in Hot Rod Magazine in 1984. The fantastic photos of Smokey in the magazine captured him wearing his trademark cowboy hat and smoking a pipe next to his vapor-powered Fiero. That made a lifelong impression on me.
Smokey Yunick spent decades working on a vapor engine.
Fast forward nearly three decades to 2013, before we had officially opened Hill Country Performance in Spring Branch, Tex. We were giving a new customer a tour of the place, showing the hot vapor engine and sharing its history.
After seeing the engine, he said, “Hey, I just saw that car on eBay.”
My jaw dropped. Years earlier, I had purchased all of Smokey’s hot vapor engines from his family's friend, Tony Allers. I also have the original door from Smokey’s shop, his honing oil, jigs, and many of his original power tools, thanks to Tony. But I didn’t have any of the hot vapor engine cars.
The hot vapor engine's magic carburetor
So, I went a little nuts when I discovered that one of Smokey’s hot vapor vehicles—the Plymouth Horizon—had just sold on eBay. Fortunately, I found the new owner and eventually convinced him to sell the Horizon to me. Remarkably, the car had never left Daytona Beach. We had it shipped from near Smokey’s Best Damn Garage in Town, his famous shop, to our place in Texas.
Finding the Horizon
Back in the day, General Motors had given Smokey a Fiero—and Ford gave him a Tempo. But GM crushed the Fiero after Smokey finished with it and the Tempo vanished. (The Fiero housed at the Don Garlits Museum is a clone car with the original vapor engine.)
Meanwhile, Chrysler sold the Horizon to Smokey for $1 to avoid liability. Finding that car all these years later, after having already purchased its engine, was a truly a great thing. When the Horizon arrived at our shop, it still had had the original bill of sale with Smokey’s signature.
How It Works
Smokey’s vapor engine design uses the internal combustion engine’s wasted energy. Only 30 percent of the hydrocarbons get burnt in a conventional engine, and the rest goes out the exhaust pipe. The hot vapor engine pushes that remaining 70 percent back through the engine. The setup does a great job of managing heat, so you only need a half-size radiator.
The Horizon engine has a prototype MSD distributor and coil.
The hot vapor engine is known for its combo of high performance and efficiency. Smokey designed it to produce 1.8 horsepower per cubic inch. The 2.2-liter engine works out to a 135 cubic inch displacement, producing 243 horsepower.
The hot vapor process burns all the fuel in the engine, rather than releasing it through the tailpipe.
In 2011, we fired up the Horizon’s engine on the tenth anniversary of Smokey’s passing. First, we made sure there wasn’t any damage to the engine. I pulled the oil pan, the valve covers, and the spark plugs. Then I scoped it with the camera down the cylinders. The engine was immaculate, almost brand new.
A Future for the Hot Vapor Engine
Now that we have Smokey’s Horizon and the hot vapor engine, we continue to look for other related parts and documentation. It’s incredible to see them show up, one by one, on eBay Motors.
We found the dyno pulls documenting what the Plymouth engine did at Southwest Research Labs. And we have records on Smokey’s three-cylinder hot vapor engine built for the DeLorean DMC-12, including notarized contracts. We buy anything we can find from Smokey Yunick’s stellar career.
According to his daughter Trish, Smokey wanted a truly passionate enthusiast to take over the hot vapor stuff. And she allowed the patents to lapse so that his designs would be free to use by future generations. Many years ago, I began studying Smokey's work on this innovative process of burning the fuel in the engine, rather than releasing it through the tailpipe. Like Smokey, I believe we can be better served economically and environmentally by embracing this work. I am currently developing a new version based on this platform. The benefits cannot be overstated.
Honoring a Legend
Danny Soliz displayed the Horizon and hot vapor engine at the eBay Motors New York Auto Parts Show - opens in new window or tab. in April. The event showcased a selection of “Re-Concept” vehicles that proved just what upgrades are possible with the right parts and accessories, each of which was on display at Classic Car Club Manhattan on the eve of the 2022 New York Auto Show.
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This article is meant to provide general guidance only. Automotive maintenance, repair, upgrade, and installation may depend on vehicle-specifics such as make and model. Always consult your owner's manual, repair guide for specific information for your particular vehicle and consider a licensed auto-care professional's help as well, particularly for advance repairs.