Wheelmang

Do I need a pressure regulator

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I've resorted to an electric fuel pump on my 1926 DB 6V. No further interest, at this point, in trying to make the vacuum tank work. The fuel pump is rated at 1 - 4 PSI. Is a pressure regulator going to be required for this?

Thanks for looking

Paul

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I think it will work without a regulator if it`s 1-4 PSI,try without regulator  and tell us how it work.!

Leif in Sweden.

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Not sure I personally would put a regulator in as at 4 psi I think it would be too much but give it a go without and see, you have nothing to lose. I have actually just gone back to the vacuum system on my 27 Chev and it seems to run better now but I did use a electric pump for about 5 years while my frustration with the vacuum system subsided then the other week ago I walked out into the shed and fixed the vacuum system in no time flat all along it was a silly little falt that I didn't pick up. Don't know how I didn't see the problem before but as the frustration sets in I become more and more blind ? Anyway give the electric pump ago

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Absolutey yes to a regulator, typically a vac system relied on 0.5 to 1.0 psi head of pressureto the carb, any more than that and you risk flooding as the float struggles to hold against the excess in pressure. 

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My fuel pressure regulator adjusts in 0.5psi increments but you could place a fuel pressure gauge after the regulator to see where its at.

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when I had an electric pump, I used a regulator adjusted to 1 psi. and it worked fine.  I am happier now that the Vaccum tank is working and reinstalled

 

Good luck 

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I ran my 1927 Chevy and my 1914 Buick B-37 on low volume 6-Volt electric fuel pumps for 34 years with absolutely no problems. I always carried a spare, but only oncedid I need to use it, and that was shortly after buying the Chevy in 1979. The failed pump had been on the car for what was apparently a very long time prior to my ownership so I should not have been surprised.

 

The needle and seat was never overcome by the electric pump, but an older pressure regulator, which proved not to be necessary, did fail shortly after that initial older pump, and was not replaced.

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Unless I screwed up my arithmetic a 1/8 hole in the inlet seat calculates to 0.0490875 psi at 4 pound supply pressure.

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If the fuel pump is located in the back of the car, take into consideration the drop in pressure before it reaches the carburetor.

 

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13 hours ago, old car fan said:

No ,you need a vacuum tank,it r ran for years that way.

I appreciate your comment and I am in total agreement it needs a vacuum tank and eventually it will have a functioning one. It would have been disappointing if there was not at least one comment from the forum membership to that point. Right now I have spent more time on trying to get this tank operational than I did on a valve job. Every recommendation from this forum has been tried all to no avail. I have had the car for almost a year and just want to take it for a ride. 

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8 hours ago, cahartley said:

Unless I screwed up my arithmetic a 1/8 hole in the inlet seat calculates to 0.0490875 psi at 4 pound supply pressure.

Interesting! Should have figured there was a formula for that. Is it supply PSI divided by hole diameter? Does it change based on supply line distance and size from pressure source?

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What is a good quality 1-4 lb. low pressure regulator?  I have three rebuilt  Stewart Warner pumps that I cannot get to pump fuel.  So I installed a  4 lb max Airtex pulse pump.  This is too much pressure for the Schebeler carb.

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I have the same vehicle as you. The previous owner installed one on my engine. It seems to do fine. 6 volt pump plus a regulator regulated down to 1 PSI. Here is a video of it pumping while disconnected:

 

 

 

My vacuum cannoster seems to work though. Wipers run with it connected. The bottom looks to be epoxied or badly welded. Some rust rattling around inside too. But I might clean her up and see what she can do. 

Edited by DB26 (see edit history)

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Hi I have a 23 Buick 6volt no pressure regulator   on it for 3yrs now never had any problems. Have one on my 18 D/B 12 volt no problems for over 10yrs. and no pressure regulator on it . As long as the float is set right and the needle and seat is good. M

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I don't think your arithmetic makes sense.  4psi times the area (0.012sq in) yields 0.05 lbs or 0.8 ozs.  That is the force the float needs to exert onto a 1/8 valve to resists the incoming fuel.

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I have a gauge under the hood showing 1 1/2 Lb. and if I go higher the carb will flood. This is on a 1930 353 Cid. V8  as not all carbs are that fussy as mine is. I do run the original Johnson carb that is a pile of crap. But over 2 Lb. on any engine I think would be risky.

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All of us can give a guess at the expected results. I would suggest trying without a regulator, and idling the engine in your driveway. With an electric pump, the worst case will be at idle.

 

Personally, I think you will either need the regulator, or custom-fabricate a fuel valve seat with a smaller orifice. The Dodge Brothers used the Stewart/Detroit Lubricator (one of my favorite brands) carburetor. This really is an excellent carb. The original fuel valve orifice was 0.111 inch. With an electric pump and no regulator, I would feel much more comfortable with a 0.086 orifice. And yes, I just pulled that number out of thin air ;) Actually, this was the size orifice Carter used for a 216 CID Chevrolet with pressure fuel pump.

 

Jon.

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I use an electric fuel pump on my 4 cyl Hupmobile, and I do need the regulator. Otherwise, the carb will flood at idle (as carbking Jon suggests above). With this setup, I have driven the car all over the state of Ohio, for decades. (By the way, Jon KNOWS vintage carburetors.)

 

Edited by lump (see edit history)

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So back to my question in post 13,  I know I need a regulator what kind to buy ?  

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This is the one in my 1926 6 volt Four Cylinder Dodge Brothers. It does a good job, The pump is an airtex. The regulator is a Mr. Gasket. 

 

IMG_2085.thumb.JPG.fba1e2e9c9c08c7eb616ba0b8767fc68.JPG 

Edited by DB26 (see edit history)

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Not to tick anyone off,but I think this talk is foolish,We have over a few cars,most are vacuum tanks.We restore and rebuild as a hobby,for the simple reason it does not need to go electric.Our 20 stud has been running,without problems for 15 years,on a stewart,we took the electric pump first thing.

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 In my case, I have a 31 Auburn with a rebuilt engine . The car is almost all together and ready to go to the interior guy,  but hasn't run yet.  I have three correct Stewart Warner fuel pumps two  professionally rebuilt and one I rebuilt.  None of them will pump fuel.

 With the FP out, cranking the engine I can feel the eccentric on the cam  going around. One of the FP's is out of a 19,000 mile 32 Auburn  so the arm is in great condition.  I have to assume the eccentric on the cam has been compromised.  An electric FP seems to me my only alternative. 

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1 hour ago, old car fan said:

Not to tick anyone off,but I think this talk is foolish,We have over a few cars,most are vacuum tanks.We restore and rebuild as a hobby,for the simple reason it does not need to go electric.Our 20 stud has been running,without problems for 15 years,on a stewart,we took the electric pump first thing.

Motivation. I like it 

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