Production Years: 1928-1929
Country: United States
Number Produced: 37,931

One particularly unconventional engine came from America. This four-stroke engine had sleeve valves and was dubbed “The Silent Knight” after its inventor, Charles Yale Knight. In the Silent Knight there are ports, as in a normal two-stroke engine, but they are located at the top of the cylinders.

Two sleeves, internal to the cylinders, slide up and down to open and close these ports. The sleeves are connected to a small crankshaft synchronized with the main crankshaft. This system is called “desmodromic” as there are no springs and every motion is “positive”. The desmodromic system’s main advantages are silence and reliability. During the first part of the 20th century, valves were noisy and fragile.


In 1927, the Willys-Overland range cars was expanded by the arrival of the Type 56, a comfortable sedan whose six-cylinder Silent Knight engine had a “rectifier”. This important new feature was introduced to combat the sleeve-valve’s reputation for using too much oil. Cars with Silent Knight engines always trailed a cloud of blue smoke. The solution to this problem involved forcing excess oil through holes in the cylinder wall near the exhaust port. The oil mixed with gasoline was fed to the rectifier, where the mixture was distilled in a chamber heated by exhaust gas. This process enabled oil to be returned to the crankcase while gasoline fumes went out through the exhaust pipe. Although clever and effective, the rectifier was not fitted to engines used in Europe.

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We apologize for any inconvenience during this challenging time but it is for the health and safety of our staff and guests. Limited entry is mandated by Pinellas County and the State of Florida. We do require that all guests, as well as Museum staff wear face masks and maintain proper social distancing. The Museum is adhering to the CDC Guidelines for keeping the public areas clean. Thank you for understanding and should you have any further questions or concerns, please call 727-579-8226

Please note that the vehicles shown online are part of our collection but may not be on display when you visit. Our team is always in some stage of repair or restoration on a number of vehicles.


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Tampa Bay Automobile Museum

3301 Gateway Centre Blvd.
Pinellas Park, FL 33782 USA

Museum Hours:

Monday - 10am - 4:30 pm
Wed- Sat: 10am - 4:30 pm
Sunday: Noon - 4:30 pm


$12 General Admission
$10 Seniors (62+)
$8 Youth and Active Military
12 and under Free
Groups of 12 or More $8 pp