65- Factory Tank for EFI
 

Hey Everyone,

I finally finished building my TPI engine for swapping into my dads 65 C10. I do have a question though.

I am using the factory tank in the factory location(behind the seat). I know I need an return line for the EFI system and I am planning on drilling and tapping a return line into the sending unit(and putting a hose down into the bottom of the tank to prevent splashing).

Has anyone done this before? I am not interested in moving the tank to under the bed or anywhere else, and I really need to do this on a ultra tight budget(spent all the $$ I had for this year on getting the motor ready, need to do the truck prep-work as cheap as humanly possible for now, can go back and make upgrades later).


If no-one has done this before, I will have to do a write-up on it(planning on doing one for the motor install anyway).

Edited to add: I will be using a Ford E2000 Fuel Pump as an Inline pump, probably mounted on a fuel rail somewhere, low pressure fuel line feeding it, high pressure from the fuel pump to the motor, and low pressure for the return line from the motor to the tank.

Re: 65- Factory Tank for EFI
 

Unless someone can suggest a reasonably priced chevy equivalent that is.... :chevy:

Re: 65- Factory Tank for EFI
 

Re: 65- Factory Tank for EFI
 

Welding on a tank that contained fuel? :devil: seems mildly dangerous for someone who only has a oxy/acetylene torch....

I have looked at that pump before, but that breaks my budget for this year, probably going with an Airtex 8248 after reading reviews on the Ford E2000...

Re: 65- Factory Tank for EFI
 

I did it about 8 or 9 years ago in college. I was paranoid, so I emptied the tank and filled it with water, then drilled and then JB welded a fitting in that I could hook a hose to. Was likely overkill. If I were to just drill again I'd use grease on the bit, and make sure the tank was as full as possible. Liquid fuel will be a lot more resistant to igniting than gas vapors, which would be present in an empty tank.

Ideally though, you could use a new factory tank, and weld in the proper fitting then install it into the ride.

One idea, and not sure if there is room, is to weld a fitting and tube into the sending unit, since you could remove that.

Re: 65- Factory Tank for EFI
 

Yeah, only morons would weld or think to weld on a fuel tank without thoroughly cleaning, neutralizing, and drying the tank. I've shortened, narrowed, and welded in sumps, bungs, and ports in many gas tanks...including recently the fuel tank on my funny car to make room for my oil tank:

http://i268.photobucket.com/albums/j...psmajjplyg.jpg

Re: 65- Factory Tank for EFI
 

I have thought a lot about how best to add a high pressure fuel pump to the existing tank behind the seat so that I have a plan once I'm ready to swap the 8.1l in.

For fuel return I had the same conclusion as you did to simply braze a fitting onto the fuel sender and drop a tube down into the bottom of the tank.

For the pickup my main worry is fuel starvation at low fuel levels in the tank. I have heard that with no baffling, and a tank that is close to empty that you might starve the pickup tube during cornering. Maybe this is more of an issue with the under bed tanks than it is with the behind the seat tanks due to shape? I'm really not certain. But regardless I have given thought to adding some kind of small catch basin with weep holes to the bottom of the pickup tube on the sending unit. But I think it would be difficult to get such a thing back into the tank through the small shallow opening. Then I saw some kind of fuel mat product recently from Holley or one of the other aftermarket carb companies. I thought that might work to solve the sloshing and starvation problem. But I've not seen it used in a behind the seat tank.

I don't know whether your TPI needs a low or high pressure pump, but n I've had several pumps from bosch to trick flow recommended to me. I think all of these are rotary vane type non-positive displacement pumps that essentially use a liquid seal to be effective. As long as you can prime it with fuel, and locate it below the tank, then you shouldn't ever really have an issue with it sucking air and cavitation unless you run the tank dry. Sure it'll be a little louder but as long as you mount it using rubber pad or dampersomething then I think it'll work just fine.

Then high pressure supply and return lines are just a matter of typical fittings and adapters.

I'm curious to see what you end up doing since I don't know when I'll get around to actually doing my swap.

Re: 65- Factory Tank for EFI
 

Have you considered using a surge tank? That way, you can avoid a second fuel port in your tank and keep air and fuel starvation from being an issue. The down side is you need a second pump to get fuel to the surge tank. I have an aftermarket tank with a sump in the back. It had a return line plumbed into it so I did not need to add a line. There is a baffle and the back half is filled with foam to minimize sloshing. Works well so far.

As for pumps, I use a Walbro GSL 392. Good pump-you can get them on line relatively cheap.

Re: 65- Factory Tank for EFI
 

It seems to be that it might be easier to either buy or build your own such as the Fuel Command Center offered by FITech.

http://fitechefi.com/default.asp.pg-...lCommandCenter

Re: 65- Factory Tank for EFI
 

Hey Everyone,

I decided on and am ordering a 1/2gal surge tank. I think this is the best way to deal with this. I do have a routing question though, see the attached diagram. Is there any reason I could or should NOT do this? It would save me a significant amount of work.

In case the image makes no sense, I want to run my surge tank return to a T in the fuel line before my low pressure pump. Is this OK? Anything I missed on my diagram other than filters? (lines on surge tank indicate actual placement)

Thanks in advance!

Re: 65- Factory Tank for EFI
 

Many years ago when we first started running mechanical injection we used a 1 gallon surge tank made using a holley float bowl to control the fuel level. Google it and you will get the idea. Worked fine. The next car we built just moved the fuel cell to the front to greatly simplify the system. Something like that may work for your application.
Jimmy

Re: 65- Factory Tank for EFI
 

I could be wrong, but I don't believe you'll need the 'low pressure' return line.

Re: 65- Factory Tank for EFI
 

This will NOT work. If the goal is to purge air from system, this will actually take air from surge tank and dump it directly into low pressure fuel pump and pump it right back into surge tank. You will need return to main fuel tank to rid air from system.

Re: 65- Factory Tank for EFI
 

Yeah the problem I see is that you'd end up with the low pressure and high pressure working against each other, as the low pressure fights to draw fuel from the surge back into the loops, while the high pressure is trying to draw from the surge and push towards the engine. You've essentially got two pumps sucking from opposite ends of the same straw, unless I'm mistaken.

Re: 65- Factory Tank for EFI
 

look at fitech they have a comand center that uses the factory tank and factory fuel pump to power a EFI motor. pretty cool

Re: 65- Factory Tank for EFI
 

what I had with my Detroit in my panel was the stock tank(rear mounted). detroit filter system with their injector pump. the return line tee'd into the filler tube. worked well for over 20 years.
ron

Re: 65- Factory Tank for EFI
 

http://67-72chevytrucks.com/vboard/s...d.php?t=610694

Found this one awhile back...lookn into it too.

Re: 65- Factory Tank for EFI
 

Update: We have installed the TPI350 in truck and I bought a new sender and welded in a return line using brake tubing. Turned out pretty nice. The surge tank worked well also. All in all, great upgrade to truck.

Re: 65- Factory Tank for EFI
 

I've been trying to think of something simple for the stock tank also. 4 years later.... Anyone have any more ideas using the stock tank?

Re: 65- Factory Tank for EFI
 

As far as welding on a tank.... I think I wouldn't be as worried filling the tank with water. Afterwards let it set and dry out, but then with ethanol gas, any remnant moisture would just bond with the ethanol anyway.

Re: 65- Factory Tank for EFI
 

Have looked through this thread? - http://67-72chevytrucks.com/vboard/s...fi+in+cab+tank
Also starting on post 10 - http://67-72chevytrucks.com/vboard/s...highlight=tank

Re: 65- Factory Tank for EFI
 

I did this with a factory blazer tank. A 90 degree at the bottom of the return line pointing away from the fuel intake line will prevent sucking air into the fuel system. Also You will need to remove the filter sock off the intake line.
This would be a great time to get the tank out of the cab and use a 69 Camaro tank. You can get them baffled for EFI that look like stock 69 Camaro tanks. Keeps fuel from sloshing around and you can always upgrade later to a in tank fuel pump.

Re: 65- Factory Tank for EFI
 

You can use your factory tank and run a return line. Depends on your setup. I used the Holley Sniper Stealth kit on my 66. The kit comes with a Holley fuel regulator from which I used the return line from it back to the tank. some EFI kits have a built in regulator that you have to run a line from the FI all the way back to the tank.

Re: 65- Factory Tank for EFI
 

Im glad you posted this...this is exactly what I want to do to mine!!!!!

Re: 65- Factory Tank for EFI
 

European cars with mechanical injection (k-jet) use a small in tank low pressure pump and in-line high pressure pump. You could use the pump from those cars (MB, 80s vw and Volvo 240 turbos) on the line coming out of of the tank. For the return plumb it into the sender like above and it would work fine.