Stock tank modification for EFI...

Discussion in 'High Tech Retrofits' started by Ca-ma-ro, May 2, 2009.

  1. Ca-ma-ro

    Ca-ma-ro Member Lifetime Gold Member

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    I've come up with a way to modify my existing tank to work for EFI. Cost is less than $150, including the fuel pump. I wanted to detail the process for those who want to do this. I haven't finished, but here's what I have so far...

    This is the stock tank pickup and sending unit, which I am modifying and reusing. Notice the 1/4" line that goes through along with the 3/8". The 3/8" line is the factory pickup, I'll be using it as the return line.

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    Now I'll be adding another 3/8" line where the 1/4" line is. Obviously the 1/4" needs to be removed. I did by simply rotating it back and forth until the solder broke free and pulled it out. Then I used a torch and heated the solder and blew it out with air.

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    I needed to enlarge the hole to accept the 3/8" so I used a punch and gingerly tapped it into the hole until it was the right size. It worked well. I didn't use a drill bit because there's actually a nipple on the bottom of the sender cover that I wanted to retain so I could re-solder the new line in. I didn't get a pic of that process, but I'll put one together.

    The next thing I did was get the tank itself ready. I am using a Walbro In-Tank 225 lph fuel pump. The pump is mounted to the sending unit and it won't fit through the sending unit hole while attached to the sending unit. So it was necessary to cut an access panel in the top of the tank to mount it. I cleaned the tank out by flushing it with water for about ten minutes. Then I put about a half a quart of degreaser/cleaner, Purple Power I think, in it and shook it up and flushed it again. While it was still full of water, I made the cut in the top of the tank using a jigsaw. It cut beautifully and no boom! Once I got it open, I completely dried the inside of tank by hand. Still smelled of gas but no fumes.

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    The next few pics show the pump installed to the sending unit actually in the tank. I cut off the bottom of the factory pickup so my return will enter the tank right at the bottom of the pump. I just used stainless clamps to hold it all together.

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    And these two pics are showing how the lines will hook up inside the tank.

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  2. Ca-ma-ro

    Ca-ma-ro Member Lifetime Gold Member

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    For both the baffle and the access panel, I picked up some 22 ga. sheetmetal at Lowes. I used two pieces of angle in a vice to make the recess for the panel. A sheetmetal break would have been lovely, but I just don't have one of those. As you can see in the pics, it came out pretty well. I'm going to use screws with a lower profile head to hold it down though because I think the hex heads will rub the trunk floor pan once mounted.

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    Next I measured for the baffle and traced it on the sheetmetal, cut it out and bent it into shape. It is 9" long, 3" wide, the sides are 2.5" and 2" on the ends. Then I tack welded it together. Now, I have to say that this was the first time I had ever welded anything...ever. So keep that in mind when looking at the welds... :shock: I did practice last night and more today before committing. But the welds, as ugly as they are, penetrated well and are doing their job. Then I drilled holes to allow the fuel to flow in quickly, but flow out slowly. I tested it in a plastic tub and it worked very nicely...

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  3. Ca-ma-ro

    Ca-ma-ro Member Lifetime Gold Member

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    I positioned the baffle in the tank with the mocked up fuel pump/level sender assembly. I had to clip one of the sides to allow the fuel level float to articulate, but it worked out beautifully. I marked the location so I could weld it without the pump in the tank. Then I tacked it to the bottom of the tank. Again, very ugly welds, but they penetrated, are solid and the tank don't leak!

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    On to the pump/sender assembly. I've shown where I cut the factory pick-up line. As I said before, it will now be the return line. I just clamped the pump to the line and the return will exit at the pickup for the fuel pump. Everything lines up nicely for the electrical and fuel connections. I may have over-engineered the electrical connects and may even rethink them, but for now I think they'll work. I used a rubber grommet through which I threaded the 8/32 brass screw for the positive connect, the ground I just attached directly to the cover. I have a quick-connect that I'll connect to the screws.
     
  4. Ca-ma-ro

    Ca-ma-ro Member Lifetime Gold Member

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    [​IMG]
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    Just a note...the entire pump/sender unit has to be assembled in the tank because it won't fit through the sender hole while pre-assembled. I tried to figure out a way to do this without cutting the access hole, but it's just not doable. At least I can replace the pump through the access panel if the need arises.

    Gas tank - DONE!

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  5. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    Swweeeeet! This is how it's done, finally. I have to do the same thing and it's great to have you do the legwork for me!! What did you use to seal the access panel? Thats the only thing that would make me nervous. It looks like I could do what you did but fully weld the access panel shut once the baffle was in, and still be able to remove the pump?

    Great work and thanks for sharing

    Steve
     
    Last edited: May 2, 2009
  6. Ca-ma-ro

    Ca-ma-ro Member Lifetime Gold Member

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    I used PermaTex #2 for the sealant. It's all I could find that was gasoline resistant. I just put a nice bead and screwed it down. I don't think it will be a problem, since you can't completely fill the tank anyway...there's always a couple inches of airspace in there due to the height of the filler neck.

    If you weld it shut, you will have to cut it open to replace the pump. The pump/level sender unit won't fit through the hole assembled. You have to put the pump on the sender INSIDE the tank...make sense?

    I hope this helps a bunch of you...took me 16 hours of trial and error to get it. I'll let you all know soon just how it works...!
     
  7. John Wright

    John Wright Veteran Member Lifetime Gold Member

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    Neat!....I've been watching all of these EFI tank threads...I still haven't made the plunge into my tank yet, but the day is coming where I will need to get moving on this.
     
  8. 1st and goal

    1st and goal Veteran Member

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    Looks good, the only pics I have are of the outside of the tank.
    We used a tanks inc kit that had a small bucket thing, similar but smaller to your baffle. Knowing me, my mechanic favored acceleration over stopping so sometimes when the tank is low (under 1/4 tank) and you stop while going down a hill the car will run out of fuel and stall so I pretty much keep it between 1/3 and full tank as much as possible.

    This is the one detractor from fabbing up a tank on your own, if I had to do it over again I'd either buy one of the spectra tanks or pony up and buy one of the tanks from Ricks or whoever the hell else makes a good stainless / baffled tank.

    http://www.cardomain.com/ride/2532279/2
     
  9. Ca-ma-ro

    Ca-ma-ro Member Lifetime Gold Member

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    Id have had no problem buying the tank I needed, but the late 2nd gen tanks aren't being made, and those who do them custom are completely outrageous on price. I have about $150 in my tank, $124 of which is the pump itself. Fortunately, there are no hills around here so all I need to worry about is side slosh, which this baffle makes irrelevant...
     
  10. sbca96

    sbca96 Veteran Member

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    Yah!! Why IS that? I never heard back from the company that makes the
    early 70's tank. I guess there is no love for the 75+ 2nd Gens.:rolleyes:

    Tom
     

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