EFI In-Tank Pumps and Welding Stock Gas Tanks. A Volatile Discussion.

[Namerow]

19 hours ago, zKars said:

I have taken past fuel tanks in for cleaning and repair and they "boil" the tank first, whatever that means.

From the 'Smart Chemistry for a Better Environment' website, by D.W. Davies Co.

RADIATOR CLEANER FOR RADIATOR REPAIR SHOP USE
 

Davies “RADIATOR BOIL OUT #100” is a powdered alkaline detergent formulation used with water for heavy-duty immersion radiator cleaning, as well as in-place radiator cleaning.  The product renders better cleaning due to better penetration, grease emulsification, better rinsing and powerful scale remover.  This product also contains an inhibitor which prevents corrosion of metals by alkalies.

For Cleaning Radiator with Immersion Tank: Prepare a solution of 2 lbs. per 20 gallons of water, increase or decrease usage based on soil load.  Heat the water and maintain it at or neat boiler point.  Immerse the radiator or other parts in the hot solution and inspect frequently for completeness of cleaning.  Remove from vat, allow to drain and pressure rinse.

For Cleaning Radiator In-Place: Use 2 lbs. per 3 gallons of water in system.  Drain system, close drain and pour solution into radiator, replace cap, run motor 30-60 minutes - - drain radiator again and flush with water until water is clear. 

This agrees with my understanding that a rad (or fuel tank) 'boil out' is only partly related to the use of a near-boiling liquid and has just as much to do with the use of an alkali (such as powdered laundry lye) dissolved in that liquid. 

FWIW, I remember first reading about this process in a book* that I ordered from the UK back in the 1960's, when I was first getting interested in motorcycles (* 'Modern Motorcycle Maintenance'... where the definition of 'modern' seemed to be focused on somewhere around 1955).  The hot lye strategy was recommended for 'de-carbonizing' exhaust systems.  No reason why you wouldn't be able to use the same procedure with your Z's fuel tank, but you'd probably need to let the solution sit in the tank overnight, to compensate for the fact that it will only be near-boiling for the first 30 minutes.

Edited December 19, 2023 by Namerow

[240dkw]

I agree with Zedhead, I cut my tank in half and tig welded it back together with no problems. Once you cut it open there will be no issues with trapped fumes. I would be more concerned about any old lead lurking in the metal. Weld it in a open area or wear the proper respirator for lead fumes.

[grannyknot]

3 hours ago, Namerow said:

Nice work, for sure. Were any precautions* taken before you started cutting and welding?
(*see Jim's list of possibilities in Post #2)

I took it down to Techno strip and had it dipped.

 

[zKars]

Here is how lucky I am regarding tank internal cleanliness. This one is spotless.

Going to steam it tonight and see what I smell when done. 

Then I'll put it out in the yard with a spark plug dangling in there with a long wire and a coil and a battery....

[Patcon]

That's a really clean tank!!

[zKars]

Well I took the first step. I bought a little household Bissell steamer and steamed the heck out of the tank. Put about an hours worth of steam through it. Tank is now fume free. 

Did it outside on a ~+5C sunny day here. Nice cloud of steam coming out all the ports. Rotated around which hole I stuffed the steam hose into during the hour and rotated the tank around. That steam was immensely smelly but now the tank is odorless and spotless (not that it had much in the way of spots to start with).

I happily silver soldered up the stock fuel outlet tube that was rotating freely(and leaking) with nice MAP torch with no fear. And yes I even stuffed the open flame in the filler tube just to prove it was fume free. Granted I’m abandoning the stock feed and return fittings, should really just solder them shut. Guess I could use the return as a vent. We’ll see.

 

 

 

 

[zKars]

Progress on the EFI pump conversion this week, after a busy holiday season that saw more kitchen renovation than I cared to do. 

Decided to create a 1.25” deep flat recess to mount the Holley 12-168 pump and hanger and the new level sender. 

The opening is roughly 8 inches wide and 10 inches long. The tray I built is 8.1x10.2 and has 1.5” bent up edges. Much grinding and fitting and hammering to get close fits all around. 

More pics tomorrow after I finish welding and mounting stuff

[grannyknot]

I'm guessing that is the sock filter for the in tank pump? Does it interfere with the stock float?

[zKars]

17 hours ago, grannyknot said:

I'm guessing that is the sock filter for the in tank pump? Does it interfere with the stock float?

Yes the fancy long skinny sock is a Holley ”hydramat” fuel sucker sponge thingy. This is my strategy to make it slosh and low fuel proof for the EFI application.

I don’t intend to use the stock float and sender, I have a top mounted aftermarket unit to install next to the pump. I think you would have to create a new arm shape for the stock float to meander around the new pump and sender hardware, but it could work just fine I think. 

Edited January 19 by zKars

[heyitsrama]

What kind of motor is the pump going to be feeding? Something fast? 👀

Check this thing out, it uses a laser to sense the fuel level.

https://www.holley.com/products/gauges_and_gauge_accessories/gauge_accessories_and_harnesses/parts/19-250

 

[zKars]

On 1/19/2024 at 11:19 AM, heyitsrama said:

What kind of motor is the pump going to be feeding? Something fast? 👀

Check this thing out, it uses a laser to sense the fuel level.

https://www.holley.com/products/gauges_and_gauge_accessories/gauge_accessories_and_harnesses/parts/19-250

 

Nothing fancy, in fact just a pretty stock L28.  Reliability and drive it anywhere anytime is the objecive.

I had seen the sonic based level sensors, makes sense there would be a laser one as well.

[zKars]

Okey Dokey, got the tank mods done and the pump and level senders installed.

After careful welding and grinding, I covered the weld inside and out with POR gas tank sealer paint. Bit fun getting your hand in the pump hole with a wire brush and/or scotchbrite to clean the backside of the weld and surrounding tank area real pretty but I managed it.  

Even managed to get the stock sender arm bent to clear all the new tank occupants. Just took a small kink near the end to get it around the stalk of the new fancy sender. Figure this way you can use a stock gauge if you want to at some point, or if I’m not happy with the Amazon sender for whatever reason. AND it fills the sender hole in the tank. The resistance range is 15 to 61 ohm given the restricted movement range, vs  10-90 stock. Float hits the lower ceiling now, and sits on the fancy hydromat on the bottom. Oh well.

Notice also the nice waterproof Deutsch DT connector.

I’m very happy with this setup. Just have make short hoses to bring the connection point down in front of the tank. Can’t put them together with the hoses going upfront and the filter with the tank in place.

There is one more detail yet to be added, but will have to wait until I have a chassis to mount to the tank. This dropped area means I am missing one of the four points of contact with the hatch floor above. If the tank won’t snug up and sit nice with the straps, I’ll have to add a little leg from somewhere in the SW corner (in this picture) of the lowered area, up to the ceiling above to form that fourth leg.

Edited January 25 by zKars