Topic: Enabling Mechanicle Fuel Pump on Flat Head


Hrussell8750    -- 05-29-2019 @ 9:33 AM
  I have installed an electric fuel pump on my 1940 flat head, and the car runs great without mechanical pump. I found out that I need to reinstall push rod and pump because of oil pressure problems. My engine builder told me that a block off bushing is available to cut off the oil to pump push rod, but I need to disassemble engine to install it, Not something I want to do at this time.
I have seen cars at shows with the pump blocked off with a plate but never asked them is the rod still in position without pump.

My question is how can I run the push rod and mechanical pump, not hooked up to operate and not cause any problems? any advice on this would be appreciated.
Thank you

Thank You, Harry8750


ford38v8    -- 05-29-2019 @ 11:23 AM
  Harry, A mechanical pump may be installed with its pushrod without connection to either the carb or fuel tank.

Alan


40cpe    -- 05-29-2019 @ 1:37 PM
  A fuel pump operating with open input/output connections might be noisy, though. It would be a little work, but I would remove the manifold and put a plug about the size of the pump push rod in the bushing.


mfirth    -- 05-30-2019 @ 4:12 AM
  Why not run both pumps. My 8ba has an elect. pump for priming & fighting vapor lock, but usually just run on the mech. pump only.
Works for me.
mike


37RAGTOPMAN    -- 05-30-2019 @ 7:45 AM
  hi
wouldn't it be easier to use the original fuel pump for running and the electric pump for priming ?
problem solved ,
use a flip switch with with a light to let you know the electric pump is on,
I was always afraid of a fire if the carburetor float ever stuck, and flooded the engine, with electric pumps,
There is no safety not unless it was wired into the ignition system, so when you shut the engine off the pump goes off, modern cars have a safety relay that shuts the fuel pump off when in a accident,
been using original pump on my 37 since 1976 and no problems yet,maybe I am just lucky ?
just use a good kit,
my 2 cents, 37 RAGTOPMAN


Hrussell8750    -- 05-30-2019 @ 8:36 AM
  Thanks for the heads up, I do have it wired to the ignition switch as you said for safety.
Harry

Thank You, Harry8750


Hrussell8750    -- 05-30-2019 @ 8:41 AM
  Alan thank you for this information, I thought it would work, just wasn't sure.
Harry

Thank You, Harry8750


TomO    -- 05-31-2019 @ 8:23 AM
  Harry, most electric fuel pumps will pump through a stock fuel pump, so you can install and hook up the mechanical pump and use either the electric or the mechanical pump for backup.

I am in favor of just using the mechanical pump as it works fine and is less troublesome than the electric pumps. When you have a fuel system (tank, lines, fuel pump ad carburetor) in good condition, there is no need for an electric pump. My 40 Mercury started within 15 seconds after sitting with out being started from October to May.

Tom


len47merc    -- 05-31-2019 @ 11:43 AM
  I echo TomO's comments. Though I've never covered the full scope of Tom's Oct-May between starts, I have with a '47's restored/preserved, bone-stock fuel system, maintained and operating at peak efficiency, seen three+ months on multiple occasions and the car always started before it reached the first '10-second' starter shut-off/cool-down cycle, typically on the 7th turn-over of the engine. Just had to refill the evaporated carburetor bowl. Same result winter or summer.

You'll spend as much or more time converting/installing/maintaining/troubleshooting an electric fuel pump and/or combo system as one would taking the time to do it right the first time in restoring and optimizing the stock system. And as well, the stock system will be more dependable and easier to manage/troubleshoot short and long-term.



Steve


Hrussell8750    -- 06-02-2019 @ 7:32 AM
  Thanks Tom for the information on your 40.
My problem with stock fuel pump seems to be the ethanol fuel, it seems to destroy the gaskets in pump. I have purchased a new one from Denise Carpenter, and had to replace gaskets and diaphragm twice. I even put a fuel pressure gauge on to keep track of pressure. Worked for a month then gauge acted up and I had to replaced it. Still having issues I went for the electric pump, come to find out both gauges worked fine, at this point the electric pump pushed fuel passed the new gaskets and leaked fuel around pump. I have also tried low lead, no ethanol fuel and still a problem with pump gaskets continued. That's why I went to just electric pump this cured all my fuel problems and increased performance.
Thanks

Thank You, Harry8750


TomO    -- 06-02-2019 @ 8:38 AM
  Thanks for the explanation of your problems with the mechanical pumps, Harry.

Are you a member of RG #17? Have you discussed this problem with another RG member? Sometimes it is necessary to see the problem in order to solve it. There are many Fords and Mercurys using 10% Ethanol added fuel that operate just fine with the mechanical pump, there must be something unique about your car causing the gaskets to fail and leak gasoline onto your engine.

For an inexpensive way to keep the push rod in the engine, with minimum noise, you could try fitting a sleeve on the lower portion of the rod that would hold it at least 7/16" above the cam shaft when the sleeve is resting on the casting. The rod may rattle in the engine, so you could try installing a spring between the umbrella and the protrusion of the bottom of the fuel pump stand. The spring should be strong enough to keep the rod from moving around.

Tom


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