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The Humphrey’s Controlled-Compression Engine

Looking under the hood at the Humphrey’s controlled compression engine at a stop in San Francisco on a trip, are (left to right) Ira B. Humphrey of Denver, racing driver Freddie Ababashian, A. Black, a Ford dept. manager and Floyd Leopold, also of Denver. The press photo date is Aug. 22, 1952 and Humphrey is seen describing how his variable compression engine works. The 1949 Oldsmobile is fitted with the standard L-head six with a special cylinder head that has been made to house the system.

This system is fully described in a Popular Science article along with great pictures that gives you its principles of operation and much background information. A quick descript-ion is that it uses engine oil pressure over a spring loaded and regulated piston to keep the combustion pressure per square inch constant through the whole range of engine speeds. The Old Motor photo.

7 responses to “The Humphrey’s Controlled-Compression Engine

  1. That’s an interesting article David. I wonder which car/oil Co. bought the idea and killed it? If he doubled the mileage with a fairly simple modification it must have raised more then few eyebrows.

    • Good thoughts, it seems to have been developed at the end of the l-head era and maybe it was a band aid to get a l-head to work better? It would be more difficut to arrange it on an OHV and being more efficent maybe the gains were not as large? I also wonder if it has survived?

  2. I think the driver would have been Freddie Agabashian, a well known racer that raced midget and Indy type cars. His best finish at Indianapolis was 4th in 1953. He also drove the Cummins Diesel Special in 1952. He held the pole at Indy that year but track debris clogged the intake for the turbocharger and caused the car not to finish.

  3. Did you scroll further down the magazine (Popular Science, August, 1953) to the brief of the Austin Healy Hundred “designed for Americans?” 0 to 60 in 11 seconds, a windshield that lowers to form a “streamlining scuttle,” and a price of $3,000? Can you imagine getting one today for that? Or the new idea of the garage door that opens when bumped? Ot the Champion spark plug ad featuring “Old 16,” the Locomobile that won the first Vanderbilt Cup, at the time owned by Peter Helck? Best of all though, was the Gus Wilson and the Model Garage story with Gus saving the day as always. Thanks for a great evening’s read, David.

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