Fuel pump questions

[rambler247]

Gents,

I have pulled my fuel pump out and it is definetly toast. After dumping out about a cup of dirt and crud the seals are all bad, the actuation arms spring was broken in 3 pieces, and after much effort the pin that holds the arm in is stuck permanently. I know that pin only goes out one way, but there are very deep grooves in it from the arm rubbing and I believe that is causing it to hold fast. I know there are kits to rebuild these, but I'm tempted to cut my losses here and go with a electric pump.

Now for those of you running said pump,

Did you pipe it directly to the carb?
What would be the consequences of putting this pump back together as is and going that route?
Can I put it back in and cap off the pump with no ill effects?

I am not worried about staying bone stock, and will be replacing the fuel line in its entirety.
I will also be swapping out for electric wipers, so that is not a concern.

Any and all knowledge would be appreciated.

[gotzskillz]

I dont know much about going the electric pump route but I beleive most are running directly to the carb.

I just had the pump go out on mine as well. I decided to go with the civilian fuel pump. Its an AC 6510. Mine is a NOS I snagged off ebay so itll eventually have to be rebuilt but I needed a quick fix.

Someone will chime in with more info.

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[Blitz]

Barrman will Be your man on this one....

But I personally would plate off the mechanical fuel pump.

I dont know if it has any type of crankcase vent on it, or if it would vent the crankcase with bad seals and still be "operating the lever from the cam ".

For the electric fuel pump, you have 2 options...
A +24 volt unit or go to a +12 volt unit.

My truck has a +24 volt fuel pump now, Mil SPec, and available...

But I also installed a +12 volt hot wire and ground and fuse and switch for future emergencies, and have a +12 volt fuel pump stored in the truck.
If ever necessary, it should be a 15 minute switch out... two wires and two hose clamps and two mounting bolts.

I used a Mr Gasket +12 volt pump for a "emergency spare" and it put out 3 to 5 psi, was about 30 bucks.

Yes it is run directly to the Carb...
BUT there is a clear fuel filter before it...( between the tank and the fuel pump )
a fuel PSI gauge ( personal choice.. I recommend it) under the hood
then another clear fuel filter with interchangable filter inserts right before the carb.

I read somewhere in the past... about another engine... needing a crankcase vent as part of the fuel pump block off plate, when removing a mechanical fuel pump.

This might not matter for the Tornado, and for non race applications...

The worst thing would be... the old dead fuel pump leaking crankcase oil, due to wear and bad seals...

I think.

Paging Dr. Barrman,

Triage room 3 ...stat.

[Barrman]

These people have done great work for others:
http://www.maritimedragracing.com/th...automotive.htm

I have a mechanical pump on my Gasser M35 worked over by them.

If you go electric there are a few things to figure out. Voltage, where to put it, how to plumb it and how to power it.

12 or 24 is obviously determined by what your truck is now.

The stock M715 had trouble with vapor lock because the fuel line runs right next to the exhaust on its trip around the engine to the mechanical fuel pump. Putting an electric pump zip tied to the mechanical pump will not help that problem any.

Fuel under pressure will not vaporize as easily as fuel under suction. So, I removed the electric pump the VFD had zip tied to my mechanical pump and bolted it to the back of the under bed storage area. That puts the pump right next to the fuel tank and is real easy to hook into the stock metal line.

Metal fuel lines are much safer than flexible hose. They look better too. No matter where you put an electric pump, buy some hose barb ends that will screw into the stock lines.

That method is what I did to replace the flexible hose taking the fuel from the drivers side frame rail to the engine oil pan bolts. I removed the factory hose, put a barb on the it, ran line up near the intake, clamped it to the engine and then did flexible line to a filter and then the carb.

When I put in the 396 I made a new metal line to go up the firewall to the rear of the engine. Then flexible hose to the carb. Now with the 6.2 I have solid line to a fabbed up line that takes the fuel next to the intake/valve cover all the way to the mechanical pump and then all the way back to my firewall mounted fuel filter/seperator with a flexible line just at the end.

I spent most of my high school years trying to drive a British car everyday. That didn't happen as much as I would have hoped. Poor quality parts is part of the reason and no mechanical fuel pump contributed too. I learned then that if it doesn't say Delco or Carter on it, you might not get home. I don't think that has changed in the past 30 years. I also wished for a simple mechanical pump a lot too.

With that in mind, how you wire up the electric pump is important. I couldn't put a mechancal pump on my Mini because the cam didn't have a lobe for it. I couldn't put a mechanical pump on my 396 because the OBA compressor was in the way. I made sure there was one on the 6.2 though. I now have a back up electric pump controlled by a switch in the M715. It makes filter filling/bleeding super easy. I also use it if the truck has been sitting a few weeks to make sure fuel is there for the start.

I treat it like the boost pump on low wing aircraft. On for starting, take off and landings. It isn't needed, doesn't add pressure but will insure fuel flow if the mechanical pump breaks.

Back to wiring. Make sure you put a switch seperate from the master on/off to control the fuel pump. Otherwise, if your carb float sticks open, you will just keep pumping fuel through the engine anytime the switch is on. Kind of makes it hard to do a "hold it to the floor and crank until it fires" flooded engine start procedure. Put in an inline fuse as well.

[rambler247]

Thanks for the insight and quick replies fellas. I'm going to fab up a plate and cap off the old one for now. I am running 24v right now so I will have to find a pump for it. Blitz, where did you source yours? I will be putting in all new 3/8" fuel lines along with the pump, filters, and a pressure guage (i like that idea Blitz). If cost is not a issue another 24v pump will be kept in the truck for emergencies. As far as the old pump goes, I like the idea of it being mechanical, but I cannot justify paying around $250 to get it fixed/replaced for a motor I plan on swapping out within a few years. Essentially I'm looking to get this truck on the road for the summer with minimal $$ spent.

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[Blitz]

I looked it up about 4 months ago, while planing for a reserve.
The truck has the Military fuel Pump installed when I got it, and its still in there.

I seem to remember, it was either Erik's Surplus or Memphis Equipment... One of the two.

Just be sure its the 2 to 5 psi model... not the 10 to 15 psi.. ( spec Your engine and carb out )

I pulled the NSN off my pump and looked it up, and Now I dont have that on hand.

Let me say that I have a Holley Carb on a 292 SBC.
I need the low pressure 2 to 5 psi.

The Tornado may need the 5 to 9 psi unit...
Be sure to spec it out.

http://www.ebay.com/itm/24-volt-FUEL...05b697&vxp=mtr

this is the design of mine... from looks alone... not speced out in the ad:

http://www.ebay.com/itm/MILITARY-SUR...01e549&vxp=mtr

[Blitz]

just noticed, made by BENDIX.

obviously repairable... springs and seals.

Sorry I dont have the exact source or number...

Its probably on another computer , in the barn.

[wantapinz2]

After changing the fuel filter and having the tank refurbished and rebuilding the carb my stock motor still ran like crap and died for no apparent reason. I decided to put in an electric 12volt pump. After. Ordering everything from summit, plus a new holley 2bbl. I thought I would give the civilian mechanical pump a try. ,what a difference. I should have done this a long time ago. The original pump was shot. The civilian version lacks the vacuum pump for the wipers but I was panning on electric wipers anyway. I got it from http://www.KaiserWillys.com
Part #930144. I hour start to finish, and only $65.69.

[MrNeutron]

I considered going electric, but I couldn't figure out a safe way to kill the electric pump if there was ever a fire. I kept immagining what if the truck rolled over and the fuel pump kept pumping gas into the engine compartment. So I decided to rebuild my fuel pump. Which was really simple. My plan B would be to just buy a civilian mechanical pump that is a direct bolt on except that it's missing the vacuum for the wipers. I think this is a civy version:
http://www.kaiserwillys.com/product/...llys_fuelpumps

[militarypotts]

Question for Mr. Barrman, on another post I talked about my truck having vapor lock during the Memorial Day Parade. It was pretty warm outside, truck ran perfect until the last block, then it acted like it was starving for fuel. It bobbled and died. Vets marching behind me yelled out "this truck is going to finish this parade" and with that 5 vets started pushing the rest of the way.
After the ceremony ended, the truck started right up and ran perfectly all the way home.
Any way to combat this situation? Thanks.