keithb7

What’s the story on old fuel pumps?

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I heard or maybe read somewhere about the vintage vacuum fuel transfer system. From the tank to the carb. The invention was patented and supposedly fiercely protected. All car manufacturers  were paying licensing fees to the company that owned the patent. Prices were steep. They had the market locked up pretty solid. 

 

What happened next? Was it true someone had enough and said, “We need to come up with a new idea. Get the fuel pump prices down.”  Then got to work designing an alternative?

When did the diaphragm mechanical fuel make its debut? Who invented it? What cars used it first? Seems to me it had a pretty good run. Into the late 70’s maybe? Eventually fuel injection caused its demise I believe.  Thx. 

Edited by keithb7 (see edit history)

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know Chevrolet used the diaphragm fuel pump starting in 1929, as 1928 had a vacuum fuel tank on it.

rebuild the one on my car, and a spare on the shelf

 

 

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Thanks @BearsFan315. Late 1920's seems about the right time they started showing up in mass produced cars. If so, they certainly had a long run in mass production. A few pump improvements here and there but it seems the basic principles of operation and design, stayed mostly the same.

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From page 97 of The Birth of Chrysler Corporation and Its Engineering Legacy by Carl Breer:

Stewart Warner was the primary source for the vacuum tank patented by Webb Jay. His high profit monopoly price induced others to attempt to break in. Bill Sparks of the Spark Whitigan Company of Jackson approached us with a vacuum tank much cheaper and better and, he claimed, free of patents. However Stewart Warner stopped him by a patent law suit. Others had tried too and were stopped. The high profit margin induced the Albert Champion Spark Plug Company at Flint, Michigan to develop a camshaft-operated gasoline diaphragm pump. However, it would require changes to the engine block and the addition of an eccentric cam on the camshaft. In its favor was low cost, and provided constant gasoline flow.

 

For what it's worth, on Plymouth the mechanical fuel pump replaced the vacuum tank in 1930.

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Another early alternative to the vacuum tank was an engine driven air pump to pressurize the fuel tank in some production vehicles.  

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Another case where a patent stifled development. Have a few because my employer insisted but the law has not kept pace with technology. If going to exist at all then should be for 5 years max. Copyright law is even sillier.

 

ps started with the Selden patent & ALAM and included vacuum tubes, radios, power steering, and many others

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Without patent protection how many new things would get invented? Patents last for 17 years. Not a long time to design, develop, manufacture and sell something and make a profit before it becomes public property. In other words, you could make anything patented before 2002 and not worry about being sued.

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To my knowledge, the only mfg that had fuel pumps as early as 1928 were Graham, Olds, Pontiac, and Studebaker. Most of the others put fuel pumps on in 1929 or 1930. I would guess that the story of the lock on the patent is an urban myth, but I really don't know. I would venture to say that by the time 1928 came around, most of the cars had larger engines that required higher fuel demand and the vacuum pump just couldn't cut it. The need for higher fuel demand created the invention of the mechanical fuel pump.

 

Frank

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While most of the vacuum tanks one sees would be Stewart-Warner; another brand of vacuum tanks was Kingston (Byrne, Kingston, and Company).

 

Jon.

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My '29 Pierce has a mechanical fuel pump.

I am not up on the earlier, six cylinder Pierces to know if they used a pressurized fuel system all the way until '28.

My '26 Rickenbacker has a vacuum tank fuel system.

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AC fuel pump catalogues show the first mech. pumps in 1928: Auburn, Graham-Paige, Oldsmobile, Pontiac, Studebaker. The GMC T50 truck was in 1927.

 

Stewart-Warner also made mechanical pumps, very similar to the AC pumps. I believe AC took them to court for patent infringement and won. All SW's dies and stock were sent to AC. Unfortunately, I have not seen a SW catalogue.

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I am sure that Stewart had many patents for the vacuum tank fuel delivery system. It was a far cry better than the limited pressurized and gravity fed systems available for higher end cars in the early '10s. Some lower cost cars continued to use gravity fed systems well into the 1920s. Stewart's vacuum tank was a marvel of Rube Goldberg design,  and incredibly reliable when they were relatively new. Even today, taking the best parts from a couple hundred-year-old Stewart tanks can result in a relatively reliable working system. I have had a few antique cars over the years with them, and many miles and several years of trouble-free service once the old tank was dialed in and working right.

I don't believe that patents were the driving force against the vacuum tank. For one thing, there were several other companies that did manufacture other designs. There were other technologies available, including the aforementioned pressurized gasoline tank. Both mechanically pressurized and the much cheaper exhaust pressurized systems were used on many cars. There were driven piston pumps, vane pumps, among other options. The Stewart tank became the known, the reliable, and easily serviced best system for most cars. Everything from Ford's low-price competition Chevrolet on up to the American assembled Rolls Royce used Stewart tanks. Even some Pierce Arrows of the '20s used them, including the series 80 I drove on so many tours years ago.

And, there was nothing Earthshaking about the appearance of the mechanically driven diaphragm pump. It had been around for a fair number of years. The problem with it was that for an automobile, at the speeds, the long hours of hard running.  The uneven demands under different conditions. The heat, the cold, the chemical exposure, etc etc etc. They were NOT reliable! I read some years back (do not remember where?) that diaphragm pumps were being tried on automobiles around 1920. They worked well. But only for a short while. The Stewart by then had been giving several years of reliable service to many hundreds of thousands of automobiles!

Stewart's vacuum tank appeared on numerous marques in 1914. In 1928, there were only a few years left on those original patents. So why did the diaphragm mechanical pump suddenly appear and quickly take over? Simple enough. Materials technology finally caught up with the need. A new form of partially synthetic rubber was available that could withstand the heat and the chemicals and the long hours and the abuse required for automotive use. And still,as late as 1932, a few makers still sold models using Stewart's tank. I suspect only because altering the existing patterns and molds for the engine would cost more than the less expensive diaphragm pump would save.

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Zepher, large-series Pierces (32/33/36 of 1921-28) continued to use the pressure system through 1928, but the Series 80/81 (1925-28) used the Stewart vacuum tank.

 

As for "reliable" mechanical pumps, during the late 50s and early 60s, my experience was that the life expectancy of a rebuilt mechanical pump was about 20-30,000 miles for daily driver cars from the 30s, 40s, and 50s.  The in-tank electric pumps of today are more reliable by far.

 

My experience also is that a vacuum tank needs to opened and cleaned about every 20 years to remove gasoline residue and remove "whiskery corrosion" (my technical term) from the suction and atmospheric valves in the lid.

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13 hours ago, wayne sheldon said:

They were NOT reliable! I read some years back (do not remember where?) that diaphragm pumps were being tried on automobiles around 1920. They worked well. But only for a short while.

I think part of the problem was the alloy they were made from. It was ZAMAC die-cast. Maybe they didn't fully understand the difference between strength and stiffness. It was strong enough, but not stiff enough and deformed under running temperatures and stress. The early bases had quite a light top flange with stiffening ribs underneath - the flange on which the diaphragm and top were attached. The diaphragm must have been somewhat soft too: the base deformed in a wave pattern between the screw holes as the screws were tightened too much and compressed the diaphragm. The stiffening ribs were in the wrong direction to prevent the wave deformation. Also, if the stirrup holding the glass bowl on was tightened too much, it bent the top and it leaked. So they attempted to suck air, at the glass bowl and around the diaphragm. Bent tops and bases can be fixed, gradually, with boiling water, clamps, flat surfaces (e.g. an offcut of steel plate) and patience.

 

If you look at post WWII replacement pumps, even for the very earliest mechanical pumps AC list, you find a much thicker, uniform thickness, upper flange on the base. The metal is also better - Aluminium. The mounting flange is also thicker and stiffer so it stays fully in contact with the block. They are now stiff enough and much less prone to deformation in service. The pump shown above by @BearsFan315 is such a pump with thick upper flange and heavy mounting flange.

Edited by Spinneyhill (see edit history)

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