Q&A: May 30, 2019 Edition - Old Cars Weekly

Q&A: May 30, 2019 Edition

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Q. My family’s moving and storage business was started in 1911 with horses and wagons here in Shreveport, La. I think this may have been one of the first trucks the company owned. Can you tell me its age?
— Joe Herrin, Shreveport, La.

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A. This photo has already appeared online, with various opinions expressed. Let’s take it step by step: It’s obviously a “Brass T” Ford with brass radiator (and lamps, if it had them, but we can see it doesn’t). That dates it as before 1917, when radiator and lamps became black-painted steel. The front fenders do not have a curved profile ahead of the axle, which makes them post-1910. The “straight” fenders in 1911 and 1912 had a “bill” on the leading edge, which these do not. According to Bruce Macauley’s definitive “Model T Ford: The Car That Changed the World,” the bill was eliminated in 1913, then reinstated during 1914. This makes the car a 1913 or early ’14.

Now it gets interesting. The license plate is of the pattern for Michigan in 1915, ’17, ’18 or 1919. Based on the shape of the dies used for the numbers, I think the photo was taken during 1919. Louisiana plates looked nothing like this in that period.

Q. I would like to know the difference between a fluid coupling and a torque converter.
— Harold Sanders, Edwards, Mo.

A. In short, a torque converter is a special type of fluid coupling. The basic fluid coupling has no torque multiplication capability. Envision two fans operating in a tunnel, one with a motor and the other hooked to some sort of output shaft. The air pushed by the powered fan will cause the output fan to turn, but cannot achieve full transmission of power because of slippage. A fluid coupling is much the same, but a fluid, usually oil, replaces the air in that first example. The input fan is called a pump or impeller, primary wheel or input turbine. The output fan is known as the turbine, output turbine, secondary wheel or runner.

A torque converter adds a third element, a stator, between the impeller and the turbine. The stator is not actually static, as the name implies. It has an overrunning clutch that prevents it from turning backwards. There are three stages in torque converter operation. When the vehicle is stationary, the stage is called “stall.” At this stage, maximum torque is applied to the turbine and the vehicle starts to move. As it gathers speed and the difference in rotation speed of the impeller and the turbine becomes less, the transmitted torque drops. This is the “acceleration” stage. Finally, as the turbine reaches about 90 percent of the impeller speed, the converter is said to be “coupling.” Torque multiplication has ceased, and the device is acting like a basic fluid coupling. In modern automatic transmissions, there is a lock-up function that comes into play, giving essentially the same efficiency as a gear transmission.

Early Hydra-Matics had only a fluid coupling, like that in Chrysler’s Fluid Drive. The difference in the two approaches was mainly that the Hydra-Matic shifted a four-speed planetary transmission with hydraulic pressure, while Fluid Drive used a gear transmission that required the driver to lift off on the throttle while vacuum or hydraulic pressure made the shift. I believe Buick’s 1948 Dynaflow was the first to use a torque converter, a five-element type with two turbines and two stators, which was very smooth. Dynaflow also had a two-speed planetary transmission, but the low gear had to be manually selected. The basic elements of the torque converter had been tested in military operations during World War II.

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