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The 1929 Willys-Knight Coupe and Its Sleeve Valve Design

American  /   /  By Mark Bach

Many hot-rodders are familiar with the Willys coupe from the 1940s. But John Willys, an early automotive entrepreneur, produced several previous noteworthy automobiles, including the innovative Willys-Knight—featuring the sleeve valve engine.

eBay currently has two of those models available: a street-rod 1929 example and a restored 1928 four-cylinder Willys-Knight Model 56.

Here’s a gallery of the 1929 Willys-Knight updated hot rod:

Discovering the Sleeve Valve

John Willys got his start selling and repairing bicycles. Still in his twenties, he expanded his operations across the eastern United States by 1900. That’s when he branched out to selling Pierce and Rambler automobiles—moving on to Willys-Overland vehicles by 1909. The Overland 38 is considered a predecessor to the rugged Jeep-like models that would follow decades later.

But the story of nearly forgotten Willys-Knight dates to 1913. While on vacation in England, Willys learned about the Knight engine that used a sleeve valve, instead of the then-popular poppet valve.

Willys didn’t want to pay royalties for the valve design. So he bought the Edwards Motor Company, the firm holding the rights to the sleeve valve.

The poppet valve is similar to what’s used in today’s engine. Early poppet valves functioned best at lower RPMs. But the metal work from the early 1900s was relatively crude so valve seats often broke. Meanwhile, the sleeve valve had these advantages:

  • Fewer moving parts
  • The potential for more displacement
  • Greater power with less sludge and carbon deposits
  • Noticeably quieter performance

By the mid-1930s, the quality of the metal materials improved. With the rise of poppet valves, the use of less-reliable sleeve valves declined.

The Birth of the Willys-Knight Brand

By 1914, the Willys-Knight brand was offering sedans with the revolutionary six-cylinder sleeve engine. A four-cylinder engine entered production—followed in 1918 by a V-8 variant.

Despite the brand’s success, Mr. Willys was in and out of financial trouble throughout the 1920s. Nonetheless, he managed control of the company for most of the Roaring Twenties, averaging a whopping 50,000 sales a year during the decade.

1929 Willys-Knight Front - The sleeve valve engine was under the hood

This ad from 1928 championed the benefits of Willys-Knight engine design but was already trying to reduce premium pricing.


The Willys-Knight run ended in 1932 when the company switched to less expensive models, including the Willys-Knight Six and the Willys 77. John Willys died three years later, well before the eponymous coupe entered the marketplace.

Two Willys-Knight Cars on eBay

1928 Willys-Knight Model 56The 1929 model on eBay (shown at the top of this post) was customized into a street rod. The seller indicates the roof and running boards were custom-made, along with front and rear belly pans.

The car features a Chevy 350 small block, backed up to a 700R4 automatic overdrive transmission. Of course, the sleeve valve design is long gone. The car has power steering, Vintage Air, power windows, and a Sony sound system. The seller invested more than $130,000 in the build, performed by Franklin Body Shop of Mansfield, Ohio.

The seller of the other example, a 1928 Willys-Knight Model 56, says it was restored to its original condition in the 1970s. Its four-cylinder engine is served by a manual transmission.

Despite high-volume production in the 1920s, Willys-Knight cars are a rare sight. After all, it has been nearly a century since production. So, when two models are offered at the same time, it’s worth pausing for a moment to consider the legacy of Willys-Knight and its sleeve valve engine.

About the Author

Mark C. Bach has oil in his veins and remembers feeler gauges and brake springs. He has a love for all things that move, especially old-school muscle cars. Bach writes for a variety of outlets, including Chevy Classics and, and maintains

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