looking for advice on which electric fuel pump to get

Ohmess

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Mark -- as another option, I mounted mine using the bolts that hold the subframe bushing to the carrier. I chose this location in part because the fuel line in that area was dented badly and I wanted to remove the dented section of line. Both my mounting location and Steve's take advantage of the bushings used to mount the carrier to the body of the car as another layer of isolation from the vibration of the pump. If you mount to the underside of the trunk floor using the location in Markos' picture, or if you mount the pump in the area around the gas tank, you will have less isolation and more pump vibration transmitted to the body of the car.
 

pickman

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Yep and I added some additional damping to the included isolation mounts and it is not audible when engine is running. Mounted under car not in trunk.
Steve - You have provided good advice on the Weber tuning - I am waiting to get my interior installed and then begin in earnest. My motor is a converted 3.5 injected to non injected (obviously) reading thru this I need some advice. I had to add an electric fuel pump as there is no provision in the head for a mechanical and am wondering if I have the wrong pump- which may be causing some of the issues? I jut bought a low cost pump at the local store to get the car running- what do you think- please.
 

Ohmess

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Pickman - there are lots of pumps out there that will get you started. Look at the specifications on the pump and report back on its operating range.

Not sure what problems you may be having, but if you are having fuel delivery problems I recommend checking the fuel levels in the bowls. How much fuel is is the bowls depends on the operation of the needle and seat along with the floats. By way of example, a common fuel flow problem that arises with brass floats occurs when the solder joints deteriorate, fuel enters the float, and the float no longer floats.

Steve sent me a good article on measuring float levels, but I can't put my finger on it right now. However, here is a copy of something I posted on a DCOM facebook page that Steve manages:

The float tab settings are designed to accomplish two thing: (1) a fuel level in the carburetor of 25mm and (2) a float drop of 2mm. When setting the distance between the float and the top of the carb with the top held level on a flat surface, you are setting the fuel level. When setting the distance between float and the top with the floats hanging all the way down, you are setting float drop. Thus, even after you set the floats to the spec in the tuning manuals, you should check where you end up.

To check the fuel level, I took a zip tie, drew a black line in the middle with a sharpie, and then cut off the end of the zip tie at exactly 25mm from the bottom of the black line. To use this, run the car, and right after shutting it down, pull one of the emulsion tubes. Shine a flashlight into the carb so that you can see the fuel in the bottom of the tube well and move the zip tie slowly into the tube. When it hits the surface of the fuel, the reflection will change. The bottom of the black line should be at the top of the tube well. If it is not, you need to change the first of the two float settings until this measures 25mm.

Once this is done, the second float setting determines the travel of the float. Both the spec for brass floats (travel distance of 6.5mm) and the spec for plastic floats (travel distance of 12.5mm) are designed to achieve the same 2mm of travel. The 2mm measurement is determined from the float needle ball with the float tab resting on the needle ball, but not depressing the needle ball, compared to the distance between the float tab and the needle ball with the floats fully extended. The full extension measurement can be made with the float top setting on a flat surface held level as with the first setting, but turned on the other end of the top. Obviously, this 2mm distance is difficult to measure; setting the travel using the spec for the type of float (6.5 or 12 mm) should get you to the same place, but this travel distance needs to be set after getting the fuel level to 25mm and measured from that tab setting.
 

mark99

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If you mount the pump using bolts that mount something else, and there is a layer of rubber for vibration isolation, wouldn't that prevent the bolt from being torqued properly?
 

Markos

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If you mount the pump using bolts that mount something else, and there is a layer of rubber for vibration isolation, wouldn't that prevent the bolt from being torqued properly?

It would if you basically had a big rubber washer. The way OEM’s do it (including the CSI/CSL d-jet pump) is to use these:

 

mark99

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It would if you basically had a big rubber washer. The way OEM’s do it (including the CSI/CSL d-jet pump) is to use these:

Mark, my question about rubber mounting a torque was regarding Steve's and similar, 'reusing' an existing mounting bolt / hole
The isolators you show would require new holes
 

Stevehose

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What Ohmess said. For triple Webers you want high volume and low pressure (2.5-3psi). Check the specs and let us know.

Steve - You have provided good advice on the Weber tuning - I am waiting to get my interior installed and then begin in earnest. My motor is a converted 3.5 injected to non injected (obviously) reading thru this I need some advice. I had to add an electric fuel pump as there is no provision in the head for a mechanical and am wondering if I have the wrong pump- which may be causing some of the issues? I jut bought a low cost pump at the local store to get the car running- what do you think- please.
 

Mike Goble

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For my dual Webers on a B35 I use the VDO lift pump from an e12/24/28/30 and the bracket from an E24. It supplies the carbs with plenty of fuel and fits right into the stock hole. The fuel sender works adequately as it's somewhat non-linear but you will know when you need gas.
 

Ohmess

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If you mount the pump using bolts that mount something else, and there is a layer of rubber for vibration isolation, wouldn't that prevent the bolt from being torqued properly?

My pump is quite a bit smaller than Steve's. It is held in place with a wrap around metal strap that has a rubber lining between the strap and the pump. Thus, the bolt is merely squeezing on the two ends of the metal strap. In addition, I am quite a bit less particular about torque specifications on a part that is not intended to move (as opposed to bolts on rotating parts, which I torque carefully).
 

mark99

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My pump is quite a bit smaller than Steve's. It is held in place with a wrap around metal strap that has a rubber lining between the strap and the pump. Thus, the bolt is merely squeezing on the two ends of the metal strap. In addition, I am quite a bit less particular about torque specifications on a part that is not intended to move (as opposed to bolts on rotating parts, which I torque carefully).
Do you have any instillation photos? in the trunk or under the car? Make and model of pump?
Thanks!
 

pickman

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I found the specification on the electric fuel pump the operating pressure is 2-3.5 PSI @28 GPH. I have dual downdraft Webers 32/36 DGV. The plugs show too rich a mixture - have good advice to tune the idle screws and linkage - but need to make sure I have the right fuel pump- the pump is a Mr. Gasket 42S.

Please advise.
 

Mike Goble

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If you have a BSFC of 0.5 lbs/hr/hp ( a fairly standard number for an older carbureted engine ) a 28 gph pump will support about 336 hp.
 

Markos

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If you have a BSFC of 0.5 lbs/hr/hp ( a fairly standard number for an older carbureted engine ) a 28 gph pump will support about 336 hp.

Added. I had to google that one...
 

pickman

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The pump I purchased was only to see if I could get the engine to run-it runs. Now I need advice as to which pump is best for this application.
 

Mike Goble

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The pump I purchased was only to see if I could get the engine to run-it runs. Now I need advice as to which pump is best for this application.
From my point of view an in-tank pump is best. I use the VDO lift pump from one of the early 2-pump systems.
 

Markos

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From my point of view an in-tank pump is best. I use the VDO lift pump from one of the early 2-pump systems.

I really like the cleanliness of this option. Do you have any inclination of the volume and psi of a stand-alone OEM lift pump? Will triples be moving more fuel than 32/36 down drafts? I would think that in theory the answer is no. If they don’t mocr
more fuel and more air, how do they create more
power?

The only carbs I have ever worked on were on lawn mowers. :D
 
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