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exhaust pressure driven petrol pump


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Does anyone on the list have a exhaust pressure driven petrol pump off an early 1915ish American LaFrance?

What other relatively common American car of that 1915ish era used an exhaust pressure driven pump I could get??

How do they work anyway??? Do they have a diaphram that pulses with the pressure of the exhaust pulses and a one way valve down the line to keep the pressure in the line???

I will in reality have a electric petrol pump and pressure regulator hidden under the seat but I want to have the exhaust pump on the car to look the part.

Regards

Gavin

1915 Type 12 American LaFrance Speedster

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Do you mean a "vacumm fuel pump"??? Should be piped the the intake side of the manifold. Not the exaust. The most Common is a "Stewart Warner".

Another system I have seen was on late 20's Cadillacs, It ran off of the oil Pressure. Gravity Feed is very common. And also, Some early cars had a small air pump that pressurised the fuel tank to two or three pounds forcing the gas to flow to the Carburetor.

I've never seen an "exhaust pressure" (petrol) Fuel pump. smile.gif Dandy Dave!

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Hiya Dave,

Thanks for the reply.

The car had a hand pump to build pressure in the gas tank when doing the first start of the day. When the motor ran the exhaust pressure did the job.

Not the vacumm type.... the parts book definatly has the pipe with the words "to exhaust pipe".

I am pretty sure my 1915 Fiat has the same system but it's pump is also missing!

Regards

Gavin

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My 13 Buick is modified with exhaust pressurized fuel delivery. We used copper tube & fittings to connect the 1/2" threaded hole on the exhaust manifold (formerly used for carb heat. This presssurizes the fuel tank so we don't run out of gas on long steep grades (because backing up hills is no fun...).

The exhaust goes through the copper tube to dissapate heat, through a spark arrestor and then through fuel tubing and into the side of the fuel filler neck under the seat(like a radiator overflow tube).

With a sealed fuel cap, this system keeps the ideal pressure on the fuel to the carb while displacing the air in the tank. It is very safe with no air in the tank to allow ignition. I have run with this system for over ten years without problems.

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Hiya Mark,

Thanks for that info. It makes me think my system might be just the same and the thing in the parts book is just a pressure regulator....

So it's not a "pump" with a diahpram or anything as complicated as that.... just a filter and regulator...

Do you have any control on the petrol pressure getting to your carb in your system at all?

What do you use as a spark arrester?

Regards

Gavin

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Gavin,

The spark arrestor came from a motorcycle shop. Exhaust pressure is only 3 - 5 psi and needs no regulation. It just gently pushes fuel into the carb at a pressure the cork float valve can easily handle. No moving parts either!

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Great stuff Dave! Thanks so much for taking the time to scan those pages for us. Just out of interest what are the details of the book as I might look out for a copy.

I love period "motor engineering" type books and I have quite a few early ones already.

The check valve would most likely be nothing more complicated than a simple spring and steel ball that seats one way and lifts off against spring pressure the other, do you think?

The LaFrance system had a regulator to adjust the pressure coming from the exhaust, which I expect is just effectively a simple bolt threaded into a chamber.... the more it goes in the more it restricts the flow...

I love the learning curve you get restoring old cars!

Regards

Gavin

New Zealand

1915 American LaFrance Type 12 Six Speedster

1915 Fiat Tipo 2 skiff

1970 Rolls Royce Silver Shadow

1978 308GTB Ferrari

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Just reading this post and never owning a vechicle that didnt have a fuel pump I would think this system would be vary benafical to any car haveing a gravity flow system. It looks vary simple,wouldnt it be possable to come right off the exhaust pipe with proper check valves,to the tank on say a model A ? My B/inlaw often spoke of haveing to back up a hill with has A,I think when low on gas.

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Check the people with pre WW1 FIATS whih used this system. Somewhere I have card of a man restoring a Tipo Zero in NZ who has an original one of these and was going to make castings and drawings for me. (I made and sent some other parts for him.) If you cannot find him or anyone else with the original feed I can annoy a mutual aquaintance for the contact details. Ivan Saxton

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