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Opinion on my fuel delivery setup.


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I filled the carb bowl though the bowl vent. Fired it up and watched the pump glass fill in about 20 seconds. Car ran out of fuel once the bowl emptied. 

Pump is rebuilt. Am I expecting too much from this pump or do you feel the float is stuck.

I've seen a few comments regarding adding the electric assist. And if needed , have it push to the pump or pull from the pump?

Tony

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If the mechanical pump is healthy, I.E. good diaphragm and valves it shouldn't have a problem keeping that Rochester 2-jet happy.  I'd check the float valve and see if that carburetor has an inlet filter hiding in the casting under that big filter adapter nut.  If it does you could try removing it and see what you get. 

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You are too early to tell.  You can either pour a little gasoline down the carburetor throat, or use starting fluid.  Use just enough of either to have the car run, but not too fast.  1 person to start the car and hold the throttle just above idle, and do the cranking when needed.  The other moderating the fuel.   

- If you use starting fluid, it is easy to regulate with short blasts. 

- If using gasoline, put a spoons worth into the carb and let the car run until it stops.  Do not pour gasoline directly into the carburetor.  A few short bursts will get the fuel system to stabilize and it should start running on its own.  

 

Sometimes you have to provide the fuel in this secondary manner to help get the fuel system established and to not burn your starter motor out.     Hugh

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I've heard to install the electric pump as close to the tank as possible.I thought of installing one on my 35 as well because if I don't start it after a few weeks it takes a long time to get the fuel up to the carb.Is that a later model intake? I thought your car used an upstart carb.

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I have an in-line fuel pump that I control with a momentary switch. I use ethanol fuel when I’m driving around often and that stuff will evaporate out of the carburetor pretty quick in the summer. I activate the pump a few seconds to fill the carburetor and it fires right up. I also had a vapor lock situation one time driving on a very hot day and I just turned on the pump and it cleared right up. 

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An electric pump, used to prime the system for startup, or to assist during vapor lock, should be mounted as low as possible, and as close to the source (tank) as possible. Electric pumps are good at pushing, but not so much at sucking the fuel. Also, you would find greater success with a rotary vane type electric pump as opposed to the cheaper "pulse" type pump.

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If you're getting gas in the glass bowl filter but the carb still runs out of fuel, I would think your float valve is stuck or the float has been punctured and filled with fuel. Somewhat easy to check by taking off the float cover.  The glass bowl should fill rather quickly, much less than 20 seconds in my experience, and do it in strong "spirts", and not a slow dribble.  

Hope this helps. 

Peter

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I have a question regarding the installation of the electric fuel pumps......I'm installing the pump on a 1940 Buick 320 straight eight. I understand the pump should be positioned close to the tank.  However...this may be obvious..... but should the pump be connected in series (in-line) with the tank fuel line that feeds the mechanical pump.  That is.... should the electric pump be pumping fuel through the mechanical pump or .....should the output of the electric pump be plumbed in downstream of the mechanical pump.

 

Thank you,

Larry

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12 hours ago, Buick35 said:

I've heard to install the electric pump as close to the tank as possible.I thought of installing one on my 35 as well because if I don't start it after a few weeks it takes a long time to get the fuel up to the carb.Is that a later model intake? I thought your car used an upstart carb.

The intake is flipped and I designed an adapter in AutoCAD that was made on a  3D printer. It will allow most 2 barrel Rochesters to fit. I never had enough original components to go all original. 

Tony

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Str8 8 Dave

I pulled the filter today. Primed the carb. Fired up and ran til I shut it off. 

The filter seemed clear enough for a newer pump but may just be to much restriction for the old pumps.

Unfortunately I did not work with a control and did loosen the top of the carb and tapped it to see if the float was stuck.

Tomorrow the filter will go back in and I'll see if the problem returns. If so I will install a larger in line filter back at the tank outlet and eliminate the carb filter.

Nice call.

Tony

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6 hours ago, larryo said:

I have a question regarding the installation of the electric fuel pumps......I'm installing the pump on a 1940 Buick 320 straight eight. I understand the pump should be positioned close to the tank.  However...this may be obvious..... but should the pump be connected in series (in-line) with the tank fuel line that feeds the mechanical pump.  That is.... should the electric pump be pumping fuel through the mechanical pump or .....should the output of the electric pump be plumbed in downstream of the mechanical pump.

 

Thank you,

Larry

Larry,

 

in my case I used a pump that could be put inline and allows the mechanical pump to draw through the electric pump. A better solution would be a vane type pump as Marty suggested however that type of pump requires a bypass with a check valve because it will not allow the mechanical pump to draw through efficiently. In no case should you use an electric pump as a primary (full time) pump and pump through the mechanical pump unless you remove the pump arm and block off the mechanical pump from the crankcase. That is what I intend to do on my REO because I want the original look but want to eliminate vapor lock issues. 

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 A word of caution not related to your fuel delivery issue. I would strongly suggest replacing the standard hardware store flat washers that is used in your manifold mounting. Without this there is a risk of a cracked exhaust manifold. Originally the were  cone shaped belleville type washers used. This allowed some thermal growth of the exhaust manifold. I always use them .I also grease both sides of my manifold gaskets. Lastly I am very conservative on the torque to secure them. I have also read that fuel pumps set up for updraft carburetors may have lower fuel pressure than required for the higher carburetor mounting. This can be taken care of by changing a spring or two. Fuel pump rebuilders can help with that. Good luck.

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2 minutes ago, raydurr said:

 A word of caution not related to your fuel delivery issue. I would strongly suggest replacing the standard hardware store flat washers that is used in your manifold mounting. Without this there is a risk of a cracked exhaust manifold. Originally the were  cone shaped belleville type washers used. This allowed some thermal growth of the exhaust manifold. I always use them .I also grease both sides of my manifold gaskets. Lastly I am very conservative on the torque to secure them. I have also read that fuel pumps set up for updraft carburetors may have lower fuel pressure than required for the higher carburetor mounting. This can be taken care of by changing a spring or two. Fuel pump rebuilders can help with that. Good luck.

I’m not familiar with this particular car but every exhaust manifold I have seen uses studs in the block with brass nuts and the above mentioned special washers.

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13 hours ago, stvaughn said:

I have a question regarding the installation of the electric fuel pumps......I'm installing the pump on a 1940 Buick 320 straight eight. I understand the pump should be positioned close to the tank.  However...this may be obvious..... but should the pump be connected in series (in-line) with the tank fuel line that feeds the mechanical pump.  That is.... should the electric pump be pumping fuel through the mechanical pump or .....should the output of the electric pump be plumbed in downstream of the mechanical pump.

 

Thank you,

Larry

 

Larry,

 

in my case I used a pump that could be put inline and allows the mechanical pump to draw through the electric pump. A better solution would be a vane type pump as Marty suggested however that type of pump requires a bypass with a check valve because it will not allow the mechanical pump to draw through efficiently. In no case should you use an electric pump as a primary (full time) pump and pump through the mechanical pump unless you remove the pump arm and block off the mechanical pump from the crankcase. That is what I intend to do on my REO because I want the original look but want to eliminate vapor lock issues. 

 

Actually,

 

I find that the mechanical (diaphragm ) pump pulls just fine through my rotary vane pump on every one of my cars,

so I have the rotary vane pump In-Line with no other lines, check valves, or other devices to complicate the system.

 

Tank to electric pump to mechanical pump to carburetor -

simple and straight system

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9 minutes ago, Marty Roth said:

 

Actually,

 

I find that the mechanical (diaphragm ) pump pulls just fine through my rotary vane pump on every one of my cars,

so I have the rotary vane pump In-Line with no other lines, check valves, or other devices to complicate the system.

 

Tank to electric pump to mechanical pump to carburetor -

simple and straight system


Interesting Marty, what pump do you use? I was advised by Carter to use a bypass. If it’s not needed that would certainly simply the installation. 
 

Steve

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Before going to an electric pump, take the fuel line off at the carb  and put a pressure gauge on the line.  Crank the engine and see what your fuel pressure is.  If you have at least 2 #'s of pressure, the next thing is to check the flow rate.  Stick the fuel line into a jar and crank the engine again and see how much fuel you  get in a given time period. If the flow is adequate  for replenishment, then you need to  look at why your carb is not accepting fuel at the proper pressure and flow rate. 

 

Electric pumps are fine for priming the system and  assisting in preventing vapor lock.  They won't correct carb problems.  In general, there is no reason why the original  pump won't  keep your car running under normal conditions.

 

Bob Engle

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I agree an electric pump should not be needed. I would simply disconnect the fuel line at the carb, stick a rubber hose over the end and put the other end in a glass jar, crank the engine and see if your getting plenty of fuel.  I also noticed you have the longest fuel line I have ever seen so the pump is pushing a lot of fuel, maybe too much.  Make sure you have the right fuel line routing as the shorter the better. 

Peter

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1 hour ago, stvaughn said:


Interesting Marty, what pump do you use? I was advised by Carter to use a bypass. If it’s not needed that would certainly simply the installation. 
 

Steve

 

Here's how a system with a bypass looks in theory:

Fuel_Flow_01.thumb.jpg.02b1b7979f0fd569f2d233e3f43ee78f.jpg

 

Here's a Carter rotary vane pump installed with bypass (arrow points to check valve).

Fuel3.thumb.jpg.8470f3e8a7c6abfa3a760f6a4ad0166b.jpg  Fuel6.thumb.jpg.e171c55d327e1be9dc2bfe7abd758bdb.jpg

 

Here's an Airtex roller vane (pulse type) which I removed and replaced with the above setup. Rubber hoses are a bad idea in a fuel system, avoid them if you can. 

7-4-18no9.thumb.jpg.6ac708929cabf5fb8375bdf6e2e2979e.jpg

 

My experience has been that rotary vane pumps like the Carter are considerably more reliable and consistent than the pulse type (technically called roller vane), but if it's just part-time for priming and vapor lock situations the roller vane types are fine and your mechanical pump can pull through them no problem so you don't need a bypass. Roller vane type pumps are notably quieter than the Carters too.

 

Your mechanical pump should be able to run the engine on its own once the carb is primed. Make sure it's healthy by testing as Mr. Engle suggests. I don't regard electric pumps as a crutch if the system is designed properly and they are set up to help with vapor lock and priming. I'm not a fan of using them as a primary pump in an old car, however, so get your mechanical pump healthy and use the electric as back-up. Your mechanical pump should easily keep up with the carburetor flow at any speed. You need to figure out if there's a restriction somewhere (a kinked line, for example) or if the pick-up in the tank is partially blocked. I had a car that ran fine and then would sputter after some driving, which I assumed was vapor lock (hence the all-new fuel system). It turned out to be trash in the tank clogging the pick up instead. The whole system has to be clean and unrestricted, even though it's "only" 2-3 psi.

 

If you like, I can send you the detailed article I wrote on designing and installing a new fuel system that might be helpful for the project.

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Am I seeing things or is your glass filter on the "gas in" line, ie., between the tank and fuel pump?   I'm not real familiar with '30s cars but every filter of this type I've seen is located on the outlet (gas out) line between the pump and the carb. The pump usually has a filter of its own inside the lower bowl.  This was how my Packard was set up anyway....

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Marty,

Thank you very much to you and to all of the other members for taking time to respond. All of your information regarding the electric pump installation was more than helpful and informative. Plan to install the electric pump in-line without the bypass and check valve and see how it goes.

Do you have any suggestions for a particular pump (Manufacture/Model) , both a rotary vane and roller vane type, for the 320 straight eight application.

 

Thank you,

Larry

 

 

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18 hours ago, raydurr said:

 A word of caution not related to your fuel delivery issue. I would strongly suggest replacing the standard hardware store flat washers that is used in your manifold mounting. Without this there is a risk of a cracked exhaust manifold. Originally the were  cone shaped belleville type washers used. This allowed some thermal growth of the exhaust manifold. I always use them .I also grease both sides of my manifold gaskets. Lastly I am very conservative on the torque to secure them. I have also read that fuel pumps set up for updraft carburetors may have lower fuel pressure than required for the higher carburetor mounting. This can be taken care of by changing a spring or two. Fuel pump rebuilders can help with that. Good luck.

I was concerned about the manifold washers but never knew what went there.

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On 11/15/2019 at 6:01 PM, raydurr said:

 A word of caution not related to your fuel delivery issue. I would strongly suggest replacing the standard hardware store flat washers that is used in your manifold mounting. Without this there is a risk of a cracked exhaust manifold. Originally the were  cone shaped belleville type washers used. This allowed some thermal growth of the exhaust manifold. I always use them .I also grease both sides of my manifold gaskets. Lastly I am very conservative on the torque to secure them. I have also read that fuel pumps set up for updraft carburetors may have lower fuel pressure than required for the higher carburetor mounting. This can be taken care of by changing a spring or two. Fuel pump rebuilders can help with that. Good luck.

I’m not familiar with this particular car but every exhaust manifold I have seen uses studs in the block with brass nuts and the above mentioned special washers.

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I’m still interested in what rotary vane pump Marty is using as a pull through. I called Carter and they said that a mechanical pump would not pull through their rotary vane pump and Matt’s picture shows the proper way to plumb a Carter with a bypass and check valve. I agree that the Carter pump is the best pump to use. 
 

Steve

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2 hours ago, stvaughn said:

I’m still interested in what rotary vane pump Marty is using as a pull through. I called Carter and they said that a mechanical pump would not pull through their rotary vane pump and Matt’s picture shows the proper way to plumb a Carter with a bypass and check valve. I agree that the Carter pump is the best pump to use. 
 

Steve

 

Sorry for the delay, but just got back from a charity event hosted by the Lagniappe Chapter of Louisiana AACA in Houma, LA. We did a picnic/car show/lunch in connection with the local Civitan at the MacDonell's Childrens' home - essentially a rescue for "throw-away" kids. 

 

As Matt Harwood has also noted , I also use the Carter P4259, and also use an older AC model (but don't have the number handy) and have had no problems despite not using the check valve. Certainly the check valve would be a worthwhile consideration. These are in use on our 1937 Roadmaster as well as our 1941 Cadillac. 

The pressure does not seem to be a concern, even on the '30 Packard, and certainly helps to clear any hint of vapor lock.

I've not gotten around to replacing the pulse type Airtex pumps on the '54 Caddy and '65 Corvair, but plan to do that at some point in the future. 

I bought the above Carter pumps for the above cars, as well as the one for our '30 Packard on Amazon Prime with free shipping, and keep a spare, as well - just in case - because we tour a lot, and may be able to help someone else, as others have helped us.

https://www.amazon.com/dp/B000CIS4IU/ref=psdc_15728151_t2_B01N0RINJB

 

Pay it forward !

Edited by Marty Roth (see edit history)
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