Jump to content

Fuel pump: factory manual or modern electric?


Recommended Posts

After replacing the fuel tank, the guy working on my '73 convertible asked me how I plan to use the car (weekend drives, local car shows, driving at night during the summer with the top down and a/c on full blast...).  Since that's only occasional driving, he suggested adding an electric fuel pump that starts when the key is on so that when the fuel drains back to the tank after not being used, it won't take as long to get fuel flowing to the carb & engine.

Sounds reasonable, and I have no thoughts that would contraindicate his suggestion.  But let's see what the hive mind says. 

Whaddya think?

Link to comment
Share on other sites

Posted (edited)

With my stock fuel pump my car does not take more then a few seconds for mine to fire up even after sitting 3-4 weeks.  It may depend on what carb you are running. 

Edited by jscott
Link to comment
Share on other sites

Posted (edited)

What is the supposed benefit of the fuel draining back into the tank when you turn the car off?  Is that a feature you are wanting to happen or something you are trying to prevent?

 

I have had a truck where there was a little bit of an air leak and fuel would drain back down from the carb when it sat.  I installed a 1way valve in the line close to the carb and it fixed it.

Edited by giantpune
Link to comment
Share on other sites

The mechanical fuel pump has a check valve that should prevent fuel from draining back to the tank. In any case, some fuel should remain in the bowls, unless you live in Phoenix or Las Vegas where the fuel evaporates in a day or two.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

Link to comment
Share on other sites

Posted (edited)

Unless you live in Phoenix or Vegas for this shit gas we get to evaporate? I live just out of Detroit and it evaporates in a day or two. But it can sit a couple weeks and all I have to do is set the choke, pump it twice and it starts every time. 

Edited by jpaz

John - 72 Q Code

Link to comment
Share on other sites

Even with increased HP, bigger carb, and sitting around a lot, My car still fires up with just a couple pumps every time with mechanical pump as well. My ignition guy put it simply one time. Even these cars were good reliable daily drivers once upon a time, so most of the parts they came with will work fine. Good luck! 

Link to comment
Share on other sites

It wasn't something I thought essential, so that's why I appealed to y'all.  Thanks

Link to comment
Share on other sites

When I built mine, after having to crank, and crank, and crank with my '80 CJ-7 [and its mechanical pump] before it would catch and fire after sitting for months and weeks on-end, I decided I would be going with an electric fuel pump - this car will never be a daily driver, after all.  It also played into my plan of eliminating as much parasitic drag on the engine [to free up more power] by taking the mechanical fuel pump out of the equation to go along with 'roller everything' (my theory, anyway).  I originally went with a Holley Blue rotary vane pump, but it was just too loud, so I switched to a Holley Mighty Mite 12-427 32 GPH unit ( https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/fuel_pumps/carbureted_fuel_pumps/carbureted_electric_fuel_pumps/parts/12-427 ).  This site said it's a good pump, but really loud ( https://www.thedrive.com/reviews/38374/electric-fuel-pump ) but I only notice it making any noise when I first hop in, turn the key to 'On,' and it starts priming the line - usually only takes a second or two.  Honestly, I like hearing that - when the sound subsides, I know I can just tap the gas once, turn the key to 'Start,' and it'll fire right up.

I mounted mine in the driver side rear wheel well, between the inner wheel house and frame, and made a nice shroud for it to keep the rock damage to a minimum.  So far, so good!

newfuelpump1.jpg

newfuelpump2.jpg

  • Like 1

Eric

mach1sig2.gif

Link to comment
Share on other sites

My $0.02 is don't start fixing a problem you don't have.

Better things to spend your time and money on.

  • Like 1
  • Fist Bump 1

Matt

Link to comment
Share on other sites

Regarding pump noises... Do not screw the pump hard on frame if you want it to be quiet. Insulate with rubber, or place it in a casing that is floating inside an insulated case screwed hard on the frame. I know mine supposed to be noisy according to some on holley sniper forum, makes only noise when the car has been parked for over a week. It then revs more than usually while building up the pressure, some high pitch for 1 or 2 secs. After that no more.

  • Like 1

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

Link to comment
Share on other sites

Just now, Fabrice said:

Regarding pump noises... Do not screw the pump hard on frame if you want it to be quiet. Insulate with rubber, or place it in a casing that is floating inside an insulated case screwed hard on the frame. I know mine supposed to be noisy according to some on holley sniper forum, makes only noise when the car has been parked for over a week. It then revs more than usually while building up the pressure, some high pitch for 1 or 2 secs. After that no more.

I have rubber grommets between the pump housing and the frame rail/mounting points.  It's really not loud at all - like I said, I like actually hearing it run when I first hop in to start it up, and then I never hear it again.  If it does start making more noise, that's a good indicator that it might be time to think about replacing it (I also have a spare in a bag in the trunk, just in case).

Eric

mach1sig2.gif

Link to comment
Share on other sites

@Mister 4x4,

It just popped up in my mind as you mentioned loud pumps. It was not about yours in particular. At the time I was looking for one, I could read often. "noisy", "like bees inside cabine" etc... which can be true if you use the frame as amplifier. Same applies to the brackets that support the fuel line(s) if you run a hard one. The pump will give the vibs thru the lines to the frame further toward the engine.

  • Like 1

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

Link to comment
Share on other sites

21 hours ago, Mister 4x4 said:

Great write up and thanks for the pics

 

  • Like 1
Link to comment
Share on other sites

22 hours ago, mjlan said:

My $0.02 is don't start fixing a problem you don't have.

Better things to spend your time and money on.

 

+1

  • Like 1

 

 

Link to comment
Share on other sites

7 hours ago, RC92234 said:

 

My pleasure.

Regarding the 'don't fix it if it ain't broke' sentiment: mine was broken beyond repair when I got it, so I decided to modernize as I brought it back from the dead.  All said and done, I think I probably only spent around $30 more for the electric pump set-up than a mechanical pump, but then again, the mechanical pump didn't fit into my plans for EFI, anyway... so that would've been money wasted.

  • Like 1

Eric

mach1sig2.gif

Link to comment
Share on other sites

In the picture of the electric pump in wheel well. I noticed you have the old toothed clamps. Next time you are at your parts store look at the fuel injection hose clamps they are smooth and to not mess up the hoses. Here is pic of some on my transmission cooler.

20200807_132313.jpg

20200807_132338.jpg

  • Like 1

When a man is in the woods and talks and no women are there is he still wrong??:P

David

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...