Electric fuel pump question

[sparkydave]

My electric pump from Moss arrived today, so a quick hookup under the hood, and it starts right up! Sweet! Now, what is one supposed to seal the threaded hose nipples with? Unfortunately, it came with a brief instruction addendum to cover positive and negative ground, but no instructions. Teflon tape? From the amount of fuel seeping past the threads, it needs something.

 

[blkcorvair]

they do make teflon tape particular to fuel that resists fuel better, But I and many have used standard teflon time and time again and it does hold up for a long period of time. Race shops generally have the better stuff. (More $)

 

[tosoutherncars]

I'll be the first to say... they work better as 'pushers' mounted down near the tank (usually on the vertical bulkhead just fore of the rear axle) than as pullers up near the carb. This is universally true, whether the pump is labelled as a pusher or puller - pumps work better when they don't have to work hard just to prime, to bring the supply 'up' to the intake.

As to the sealant / tape...

https://www.permatex.com/products/Automot...ead_Sealant.htm

Permatex makes a couple of thread sealants suitable for fuel line fittings. Your local NAPA / auto parts store should stock it.

As a lesser choice, I believe they still make *yellow* teflon tape for use with fuel fittings.

HTH!

Duncan

 

[sparkydave]

Thanks Scott! :thumbsup:

 

[sparkydave]

..And Duncan! I was planning to put it down by the gas tank to push from the rear; I just hooked it up in place of the mechanical one and ran some clip leads to the fuse box to make sure it runs. Is the yellow suitable for gasoline too? I knew it was used for natural gas. I'll check with the parts stores too, I'll need a few parts yet to make it permanent.

 

[tosoutherncars]

Excellent... well I'm putting a Carter on soon (HVLP for the Weber) which should allow me to remove the FPR so be sure to take lots of pictures, so I can steal all your good ideas!

As I understand it, the admonition against teflon is not that it will dissolve, but rather that after a few rounds of assembly / disassembly, it shreds (as we've all seen) and small pieces can work their way into the fuel system, eventually clogging up filters, carb jets etc. Personally, I'll be sticking with a Permatex-type thread sealant.

 

[dklawson]

Regarding Permatex and thread sealants, I've never used Teflon tape on fuel. However, common Permatex-2B sealant (the thick paste in a tube) is fuel resistant and makes an excellent thread sealant.

I've worked with a lot of pneumatic equipment over the years in my job. I've never liked Teflon tape. When used carefully it works well enough. However, if applied wrong or to a part that is taken apart frequently it sheds little bit of material that drift downstream inevitably to some critical location that the Teflon interferes with. That's why I've always preferred paste type thread sealants.

 

[sparkydave]

It lives!

Thanks all, I spent some quality time on the underside putting the electric pump next to the tank and running a wire from the fuse block. Pretty uneventful, I just drilled two small holes (sorry little car) at the sloping edge of the trunk floor, so it clears the rear axle and is mounted just inches from the fuel tank fitting. I bypassed the mechanical pump, and so far, it seems good. I haven't decided what to do about the mechanical pump, whether I should just leave it disconnected or take it out and cover the hole. The car started up right away, and no strange bubbles in the fuel filter or any stumbling even after it's good and hot.

 

[dklawson]

Re: It lives!

I would remove the mechanical pump and put a cover plate over the opening... but that's just me. It wouldn't take much to make your own.

 

[jvandyke]

Re: It lives!

I've got some sort of SU fuel pump but something isn't right. Gas supply is low. I'll start at filters but I'm wondering if these pumps are rebuildable? It's in the engine bay too which is a shame. I also have a decent little Carter on the shelf that was giving 23gph on my Opel, so I might just hook that up like Dave did. Although I have to deal with the whole positive earth thing yet too I guess.....

 

[dklawson]

Re: It lives!

There's a nice gear-rotor Carter pump that is low pressure and suitable for SU carbs. I can't remember the model number but I remember that NAPA sold it. If you have a different type of Carter pump remember that most are higher pressure than the SU and Stromberg carbs like. If yours puts out more than about 3 PSI you should consider installing a pressure regulator after the pump. Previous threads on this board have discussed that the Holley pressure regulator is a much higher quality regulator than the pancake one sold under the Facet and Purloator names.

EDIT: Sorry, I forgot to answer your other question. If you have an electric SU pump they are rebuildable. The diaphragm is replaced as part of most rebuilds, sometimes the check valves need attention. I think in most cases the points can be dressed and the mechanical toggle adjusted to restore proper operation.

 

[tosoutherncars]

Re: It lives!

I think the Carter is the 4070... I can check, have one on the bench, ready to go on.

 

[tosoutherncars]

Re: It lives!

https://www.racetep.com/webfuelspark.html#webfuel

 

[dklawson]

Re: It lives!

Nice pump. The link says not to use this type with a regulator. It's a 4 PSI pump so you'll be on the edge with SUs or Strombergs. The link says it will be perfect for Webers.