Can a Vaccum operated fuel pump work on a model t ford ? Thank you ..lorenzo
You should not need one but it would work if you have a source to draw the vacuum from. Since the Ford system is a gravity feed it already does what a vacuum tank does. The vacuum tank draws the fuel up from a rear gas tank to a point on the firewall that is above the carburetor and then feeds it by gravity to the carburetor. As such it would be a useless addition.
Well, not really Val. My Gramps used to run his TT in & around downtown Seattle & if you've ever been in Seattle, you would realize it was beneficial.
The Chevy type vacuum tank has about the same drop to the carburetor as the 1926-27 Model T cowl gas tank. Most Model T's have the gas under the seat which means less drop to carburetor, hence steep hills can be a problem. You can do like the speedster guys do and set your gas tank up so you can use a hand pump to pressure rise the tank slightly, 1-2 psi +-.
I will admit that in an area where you have long steep hills the gravity system might let you down but a vacuum tank is not that much better in that the vacuum system is at it's least efficient level when the engine is under a load such as going up a hill. The greatest vacuum is when you let up on the gas as those who are familiar with vacuum wipers and tops will remember. There is a reason why they switched to mechanical fuel pumps and it wasn't because vacuum tanks were so good. I summer in the Adirondacks where we have plenty of long steep hills and the Ford gravity system actually works better than the vacuum system on my 1930 Plymouth. Vacuum systems are temperamental at best. I would go for an electric fuel pump or pressurize the tank before I went for a vacuum tank. I eventually put an electric fuel pump on my Plymouth after years of chasing down issues with a vacuum tank. I am sure there are people who run vacuum tanks without issues but like the Ford Vaporizer carburetor it seem to me that in many cases they are more trouble than they are worth.
Yes it will work off the vacuum from the T manifold. The biggest problem is A; getting it to work (most only need a good cleaning and new gasket(s)) and B; finding a place to mount it. I was looking at a way to mount one on mine at one time and found there just really was no place for it. If you do find room the bottom of the tank has to be at least 3 inches above the fuel level in the bowl. Once the gas is in the vacuum tank it gravity feeds to the carb. They are not a full pump, it pulls the fuel from the tank and fills the reservoir to feed the carb. There is another type that I have seen on cars etc, it's round and takes up a lot less space but not as common as Stewart.
my Dodge Brothers cars use a stewert Vacuum tank ...the system is effecient and effective in any conditions ...they are simple to rebuild once you remove the screws that hold the tank top inplace ...ONLY problem is that if the vacuum tank is dry you will not be able to draw fuel from the tank before your battery gives out ...there is a plug in the top of the tank that will allow filling in this situation ...these tanks were common with many 1920's era cars and trucks ...always an optimist ...Gene French
I agree with Gene French.
When I was younger, my dad owned a 1927 Hupmobile for many years and it had a Stewart vacuum tank.
Never experienced any of the problems that folks claim vacuum tank systems supposedly suffer. Never any problems on hills.
This was a low mileage and very well maintained unrestored car.
My 1924 Tarrant special T tourer has the fuel tank mounted under the spare tyre carrier at the back. The 1925 Duncan and Fraser roadster I have used as a reference when restoring mine has the same set-up. In both cases a Stewart vacuum tank is mounted high on the metal firewall under the hood, on the left, seeing both cars are RHD. Only once in 4 years of motoring have I had to pull a hill long enough to cause starvation to the carb. Simply stopped and started her up again.
I do carry a small funnel under the seat in case the tank needs to be primed.
Allan from down under.
Over the years, I have had a few non-Ford cars with vacuum tanks. Most, were very reliable and I had little or no trouble from them. One, was troublesome, and I never found a solid reason why. It may have been a little troublesome? But I enjoyed driving that car for several years and thousands of miles.
My model T boat-tail also uses a Stewart vacuum tank because the gasoline tank is low and well behind the seat. I did actually have quite a bit of trouble with it, however, mostly it was not the vacuum tank's fault. The chassis had sat for a few years, and dirt and a few leaves got into the gasoline tank causing all sorts of problems. Once I got it cleaned up and replaced a failed float (maybe due to the acids left by the leaves?), it has worked very well. So far.
Generally, I have always enjoyed cars with vacuum tanks. Sometimes, they have a few bugs to shake out. Usually, once working well, they become fairly reliable. They do have a tendency to fail under the condition that you need it most as Val S mentions. The engine vacuum is lowest when pulling long hills. I usually prepare myself for a pullover to refill the vacuum tank (sit and idle for a minute if needed) and usually don't need it. One of the last Endurance Runs I went to (Gotta go again SOON!) had a long winding hill that I never pulled over for and had no trouble on.
I, too, carry a small funnel, and a small amount of gasoline in a small container. If the vacuum tank does fail? You can go a long ways by pulling over every few miles to manually fill the vacuum tank. When that float failed (and it failed massively and fast, which is why I suspect acid contamination)? I went for many miles.
I hope to drive many more miles yet on vacuum tanks!
Drive carefully, and enjoy, W2
When I recently swapped the NH for a 1930's SU carb on a Vaporizer manifold I got some gas delivery problems since the new carb sits higher. No problem, had a couple of vacuum tanks on the "can come in handy"-shelf and checked them out. The Stewart turned out to be missing its inner /upper tank, so I checked the other one, a Pallas unit made in Germany, I think.
The Pallas looked like a beautifully engineered quality product inside and turned out to work just as flawlessly, I tapped the intake, installed the large tank on the firewall, primed it and started driving - about 300 miles now without any problems - haven't got any hills that goes on for miles, though, so I can't tell how that'll work. Just some more priming needed then, I think
It appears it can but if you're starting from scratch with no parts to install wouldn't an electric pump be an easier, cheaper and less obvious solution?
Most electric pumps you can find today runs on 12 volts and gives more pressure than the float valves in old carbs are built for, so you'll need to convert the electrical system and get a pressure regulator too. Ok, there are a few 6v low pressure alternatives available, but none I've seen were cheap and who needs additional loads on the marginal std electrical system?
Don't particularly like adding any kind of pump on a T either - this is more of a period part that adds interest
I've had some experience with the Stewart vacuum fuel pumps. They need to be rebuilt and cleaned pretty much the same as a carburetor. They have a float, a needle valve, and various seals that have to be in good shape. You will probably have to "save" the original parts, repair them, and make your own gaskets because none are available.
These units are not going to be reliable if you let gas go bad in them on a regular basis. They need to be drained when the car is not going to be used for a few weeks, and they need to be refilled next time you want to drive the car.
I am pretty much echoing Wayne and Gene's comments, with the additional comment that this is added complexity that is not maintenance free. One of the delightful things about a Model T is that it requires very little maintenance in stock condition. Probably the main reason that you don't see a lot of 1920's cars on the road other than Model T Fords is that those other cars were not as simple to maintain, and the vacuum fuel tanks were confounding to mechanics when those cars were only a few years old. Thus a lot of those other cars are gone today, scrapped because they had some degree of complexity that could not be fixed by the average guy.
Just a quick note on electric fuel pumps - I purchased a 6v Carter pump from one of the major T parts vendors. It was not significantly expensive, and installation is fairly simple. It came with a small in-line filter as well. The pump provides pressure up to 4 lbs. I also installed a Holley fuel pressure regulator that provides a constant (adjustable) 1.5 lbs pressure to my Stromberg RF carb. I have it wired so that the pump is activated when the ignition is turned on. I've been very happy with it's performance for the last three years I've had the car on the road. No problems at all with this set-up.
There are low pressure 6v electric fuel pumps on the market that are available from some flat-head V8 suppliers.
Gaskets and springs ARE available for vacuum tanks through Bobs Automobila 805-434-2963 They specialize in Buick parts
I used to own a 30 Dodge that would start off the battery with an empty vacuum tank. You just need a good tank and an engine with good valves.
I have been running a Stewart Warner vacuum tank for about 40 years in a '25 TT and what Royce says is so. If not operated regularly there is the possibility of gas problems and need to reprime. Otherwise it is useful for steep hills and generally providing positive fuel pressure delivery.