Fuel pump

[clo]

Can I run a electric fuel pump through the stock fuel pump on a 59ab? Do i have to modify the stock pump?

[JSeery]

Yes and yes & no. Depends on what you are wanting to do, just use the elec pump part time or run on the elec all the time. If all the time you are better off modifing the original pump to prevent a diaphragm leak from filling the engine with fuel. Several Barn members have made this mod.

[clo]

What do I need to do to modify the stock pump?

[adileo]

You can remove it / block it off or read Vic's thread "what I did on my lunch hour" (on barn) he goes into detail on exactly what you need to do, to make it a pass through

[JM 35 Sedan]

Yep, Vic has become the "go to guy" for details on how to modify a mechanical fuel pump in order to run an electric FP full time, and have the gas go through the mechanical pump without the fear of filling the crank case with fuel.

[Vic Piano]

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Like Andy (Adileo) and JM said, I have converted a number of OEM fuel pumps to 'pass through' pumps. I've done this for ease of operation and dependability, not to mention retaining the "as Henry built it" look under the hood. When I make the conversion, I install a fuel pressure regulator (set at 2.5) and a kill switch. I also leave the fuel pump pushrod in the block. The conversion is easy and the constant fuel pressure makes driving a pleasure. All my cars/trucks are driven, not trailered, and dare I say it... the conversion to electric fuel pumps eliminates having to deal with the joy of Vapor Lock, in my experience. Try it, you'll like it.

[MGG]

Just curious - Vic why do you leave the push rod in the block? Is it a chore to remove, or not a good idea to do so?

[JSeery]

Originally Posted by MGG

Just curious - Vic why do you leave the push rod in the block? Is it a chore to remove, or not a good idea to do so?

So he can convert it back to a mechanical pump any time he wants without having to pull the intake manifold. And there is the added benefit of it partially plugging the oiling hole in the bushing.

[Vic Piano]

Originally Posted by JSeery

So he can convert it back to a mechanical pump any time he wants without having to pull the intake manifold. And there is the added benefit of it partially plugging the oiling hole in the bushing.

JSeery is correct. I always carry a 'known to be good' OEM fuel pump with me just incase the electric pump fails.

[oldford2]

Originally Posted by Vic Piano

Like Andy (Adileo) and JM said, I have converted a number of OEM fuel pumps to 'pass through' pumps. I've done this for ease of operation and dependability, not to mention retaining the "as Henry built it" look under the hood. When I make the conversion, I install a fuel pressure regulator (set at 2.5) and a kill switch. I also leave the fuel pump pushrod in the block. The conversion is easy and the constant fuel pressure makes driving a pleasure. All my cars/trucks are driven, not trailered, and dare I say it... the conversion to electric fuel pumps eliminates having to deal with the joy of Vapor Lock, in my experience. Try it, you'll like it.

I guess I don't get it Vic. Maybe I am missing something..If you have a good fuel pump and an electric pump why modify a good mechanical pump when you have an electric pump as backup in the case of "vapor lock".
John

[MDC]

This is a little off topic but I don't think my reproduction fuel pump is pumping enough fuel to my 1941 engine. Are there good ones and not so good ones? If so, which are good?

I put a clear fuel filter in the line so I can see the fuel flow which is why I don't think it works well.

Thanks.

[Roger/Sacramento]

I am running a stock fuel pump with an Airtex 12V electric pump in the fuel line near the gas tank. I switch the electric pump on to fill the carbs and turn it off when the engine starts. If I leave it on it will force gas past the gasket on the mechanical pump and get gas all over. The mechanical will pull gas through the electric pump just fine. Previously I had a different electric pump and the engine would lean out after 2000 RPM,

[Vic Piano]

John, my reasoning is simple, I've had too many manual fuel pumps fail, while out on the road. I was simply tired of making multiple road side repairs only to find that the replacement manual fuel pumps (that had all been rebuilt by an individual from the North East) were no good! One pump lasted less than 1oo yards on the highway . In my opinion (based on my experience) the electric pumps provide a number of benefits over the mechanical pumps, one that has proven to be especially helpful is the constant fuel pressure provided by the electric pump. Constant fuel pressure at speed provides instant throttle response and at idle (like when you are sitting at one of the seemingly never ending traffic lights) the pressure delivers liquid fuel to the carb, not giving it a chance to vaporize... that has vanquished Vapor Lock in my Flatheads. As I mentioned, I keep a 'known to be good' OEM pump with me incase of a failure of the electric fuel pump, not Vapor Lock. I should mention that in over fifteen years of driving Flatheads with electric fuel pumps, I have not had any reasons to go back to the manual pumps.

I like to convert the manual pumps to 'pass through' pumps just to keep things looking 'stock' under the hood.

[jimTN]

If you are running a low pressure ele pump there should be no problem since the gas will just pass thru the fuel pump valves. Just pick up a stock pump and blow thru it from the "in" side. I have several vehicles set up with a elec pump for emergency and they work fine. Only time gas would get in the crankcase would be if the diaphragm were ruptured on a mech. pump.

[Vic Piano]

Originally Posted by jimTN

If you are running a low pressure ele pump there should be no problem since the gas will just pass thru the fuel pump valves. Just pick up a stock pump and blow thru it from the "in" side. I have several vehicles set up with a elec pump for emergency and they work fine. Only time gas would get in the crankcase would be if the diaphragm were ruptured on a mech. pump.

This is true however, what if the 'emergency' is a ruptured diaphragm? How would you know what the problem with fuel delivery was, without removing and disassembling the mechanical pump? If you chose to continue driving with the 'for emergency only' electric pump as the primary source for fuel delivery, you might be unknowingly pumping a portion of the fuel into the crankcase... In my experience, chances of an electric pump failing are far fewer than mechanical pump failures. I use my Flatheads as daily drivers. Having the peace of mind that there is minimal chance of a breakdown involving fuel delivery makes each drive even more enjoyable.

[frmhrt]

Originally Posted by clo

What do I need to do to modify the stock pump?

I have this same question. Where can I find detailed instructions on how to modify the mechanical fuel pump to by pass it?
thank you

alan

[adileo]

Search Vic’s thread on this forum - the title is “what I did on my Lunch hour”

He goes into great detail on how it’s done. The post goes into many other subjects so be patient in your search for the article

[Vic Piano]

It was brought to my attention that, in an earlier post on this thread, I mentioned that I had a number of rebuilt fuel pumps go bad in short order. Those fuel pumps were rebuilt by someone in Connecticut (the North East), whose name I will not mention. There is another Barner in New York (also the North East) who's name I will mention. Charlie NY has rebuilt Carburetors for me that are outstanding. He also rebuilds OEM fuel pumps that I'm sure are every bit as reliable as his carbs however, to my knowledge, I have never used one of his fuel pumps. Sorry for any confussion my previous post might have caused.

[Planojc]

Originally Posted by Vic Piano

JSeery is correct. I always carry a 'known to be good' OEM fuel pump with me just incase the electric pump fails.

Why not just carry a spare electric fuel pump?

[adileo]

Even though Vic is an extremely fit man (been on cover of GQ mag laying on hot Florida pavement and sliding under his vechicles may be a bit tight. Not to mention the need for hose clamps and additional tools to remount new pump to frame.

Two bolts to replace fuel pump

[drolston]

Originally Posted by clo

Can I run a electric fuel pump through the stock fuel pump on a 59ab? Do i have to modify the stock pump?

Straight answer to simple questions. Yes. No.

The rest of the story:
To minimize possibility of stock mechanical fuel pump diaphragm leaking fuel into the crank case, use a low pressure electric fuel pump (~3 psi) and if the pump guts are old, rebuild it pump with modern alcohol resistant diaphragm.

You need to buy an electrical pump that does not block flow when it is not running. That way you can just use the electrical pump to prime the carb and overcome vapor lock. That is my setup. Works well, and I like having the redundancy.