claytonisbob

iTrader: (1)

Ok, let me start by saying I am swapping a LQ4/t56 in my '69 Chevelle. I don't know how many gas tank threads I've read through. My head has been spinning with ideas of what to do. I have finally boiled my ideas to 2 choices. This is because I want a tank that will have no sloshing issues on an autocross course, and I don't want to spend a ton of money. Yes I'm cheap, but I think others are looking for the same thing.



Option 1:
Essentially I want to put a in tank sump or surge tank in my stock tank. This would mean it wouldn't take up any room in my trunk like a large 1 gallon swirl pot would, and it would mean that if it filled up with fuel, it would just pour over the edge. I wouldn't have to worry about leakage. I already have a 5" cylindrical stainless container I plan on using. I'm going to mount a Racetronix pump inside this container. Now some people have done something similar to this, but they put a hole in the container to let it fill with fuel. When going around a corner or accelerating I worried about how fast the interior sump would fill or drain with fuel. Not wanting to have to test how fast gasoline travels through different sized holes I figured a one way ball valve or trap door would work best.

Now this is where I got stumped for a while. I couldn't find something like this I was wanting to use. It may exist, but I couldn't find it. Plus I'm cheap.

So I went to the hardware store and got a few of these. Its basically a copper tubing coupler, a ball bearing, and a 1/16" roll pin.


I drilled out the inside of the fitting to the size of the ball bearing (9/32" drill bit), put the roll pin vertically in one side (that has been smoothed) drilled a few holes on the interior side of the fitting to let fuel flow in when the ball is resting at/on the roll pin. And I cut the cap on the otherside to make it kind of like a bulkhead fitting.



So when you get some lateral movement in the right direction the ball will move toward the side that it seals on, and the fitting opposite of it will open up allowing fuel to flow in. When the ball is inward, it rolls past the small orifices and fuel can come in.



I am trying to decide if this will work well enough.. or at all. Any criticism is welcome.

Option 2:
Basically same exact setup, but instead of valves, I'd just use a second pump. The demands for the second pump would be minimal because it would be running without back pressure. There are some pumps on Summit in the $40 range I think would work fine.

My thought is the second pump would be mounted to the outside of the container/sump and would just pump directly into the sump. When the sump fills, it would just trickle over the side of the container.

I'd like to suspend the container from a mount in the top of the tank (a round plate screwed into the top with a gasket, I want this to be modular enough to build it and be able to just cut a hole and put it in the tank).

I've even though about using these 2 ideas together (valves + pump), as if the pump always kept the container full of fuel. The weight of the fuel would keep the ball valves sealed at all times. But if the pump went out (being its probably going to be a cheaper pump), I wont be totally hosed.

Anyway, that's my idea. Let me know what you think.

Jimbo1367

You're a IDIOT !!!!!!!!!

Jimbo1367

jk. LOL

68lsxc10

iTrader: (1)

I guess either one would work, but I have another suggestion. When I built the tank for my truck, I built a "maze" in the bottom for the pump to sit in. It is actually welded to the bottom of the tank, and is made of straight strips of metal. (Like the drawing on the left) I have never had a fuel starvation problem with this setup. If you needed one that could drop in from the top, you could make a circular one like the one on the right.
I had some pics of my tank, but I can't find them. So i attempted this crappy drawing. This view is looking down from the top of the tank. The X is the location of the fuel pump pickup. Just a suggestion.

claytonisbob

iTrader: (1)

Hmm, that's a good idea.

Do you think the dual pump idea is overkill? I think my only concerns are reliability (2 pumps mean its twice as likely for a pump to go out) and fuel temps.

Also I have a 3/8" main, 1/4" return sending unit. Do you think running my return through the 1/4 inch port would be much of a restriction? I mean it would only be over a couple inches.

68lsxc10

iTrader: (1)

I don't really like the dual pump setup you described because of the same reasons you just stated. I do like the way you made your check valves. That is pretty creative. (And your diagrams look way better than mine!) I had originally thought of using a "trap door" setup in the sump, but the "maze" seemed foolproof. No doors or valves to stick.
I would think that a short 1/4" return would not be a problem.
I do like an intank pump setup better than a external pump setup for sure. I have an intank pump in my 68' C10 and you can't hear it run! I have an external pump on my 63' Nova that is loud and acts up sometimes. I will be fabricating a tank for it soon, and it will be an intank pump.

claytonisbob

iTrader: (1)

Ha, do you have the intank pump in the tank behind the seat?

That's actually my next LS swap I want to do, a 5.3 w/ 4L60E in a '71 GMC short wheelbase. I'd probably get an under bed conversion tank though.

I have to agree, the maze is pretty foolproof and probably the cheapest way to go too. I do have a mig welding machine so that might just be the way I go. That's what I get for over thinking things.

Cool part is about doing a maze is I could probably get it set up so I can still use the stock sending unit (cut an opening in the tank, weld in the maze sump, weld it shut and make a bracket that would hold the walboro pump to the stock sending unit). We'll see how it goes, I'm going to drop my tank next week and take a stab at it.

Pop N Wood

iTrader: (1)

If you are going dual pump then I would strongly suggest putting the surge tank outside the main tank. Putting it up near the engine would be best.

Using a second pump inside the tank is putting just too many things inside the tank. Dropping tanks is no fun.

My rule is KISS. The best sump idea I have ever seen is welding a small box on the bottom of the tank then drilling three half inch holes in the tank to feed fuel to it. Drop the pump intake line into the sump. This way gravity does all the work.

Can't get much cheaper than this, and it is a lot more foolproof than any type of baffles or trap doors.

You're check valves are pretty damn creative, but my worry is they are too small to let fuel in. You're not going to have much head forcing swirling fuel into the sump. I think the fuel will just slosh around the outside of the sump rather than into it. You can use a larger diameter ball, but then you have more inertia in your check valve. The check valvue might start opening and closing with the turns rather than fuel height differences between the sump and the tank.

Plus you won't be able to get then flush to the bottom of the tank.

71ANTICARB

iTrader: (23)

I vote for the maze setup. If you do it take some pictures and post em up. I haven't really looked to much into the FI fuel tanks that are in the summit (seeings how their way out of my price range) but might look to see what kinda setup they are using. I've kinda noticed its not a bad idea to try and copy some of the tech from the name brands since they have all the money for the r&d.

claytonisbob

iTrader: (1)

This was inherently the reason I wanted to use check valves, so when the fuel sloshes towards the side gravity is pushing it, the ball will close on that side and keep fuel from leaving. Drilling holes is much simpler, but then I'd have to test how big can I make them without all the fuel pouring out through them when turning, accelerating or braking. I had planned on testing the valves when attached to my sump by submerging them in a sink of water and seeing how fast, or how easily water would go in them. The viscosity of gasoline is less than water, so I'd imagine the flow rates would be quicker.

The maze idea may be what I am going to try first. I can essentially do away with any other access holes in the top of the tank (well, I'd have to cut one, but I could weld it shut), which I'd have to worry about sealing off ect. Plus it would be able to use every bit of gas in in the bottom of the tank, whereas like Pop N Wood said, my idea wouldn't be able to sit flush enough to the bottom, so I'd be leaving at least 1/2" to 1" of fuel on the table.


On another note. I've been thinking about doing a watts link setup, but in Chevelles, gas tank interference is the biggest issue. It's just so damn close to the diff cover. I've been looking at the rear of the tank and there is a lot of room the tank could move rearward if I were to relocate the strap mounting brackets. I'd also have to shorten the filler neck, which isn't that big of a problem. By doing this, and cutting/welding or rolling the seam on the front of the tank I think it would free up enough room to install a watts link. It would move the tank at least 2 to 3 inches closer to the rear bumper... I don't know if that would make it any more dangerous. Has anyone thought of doing this? I know someone on this forum, or the pro-touring forum was testing using a Nova tank. I may just go that route when the time comes to address a watts link.

chevyboy91188

iTrader: (15)

on my chevelle its a 72 I was going to just weld a sump in the bottom of the tank and feed from there but now i may just do a swirl maze because i can use a spring type steel and just wind it up real tight and put it through the hole in the top then just drill one hole in the bottom of the take for my feed line

Jimbo1367

Very cleaver solution. How high was the "maze"?

LS1MCSS

iTrader: (18)

With your dual pump setup, it looks to me like you're going to have more **** than you can fit through the sender hole.

GC99TA

iTrader: (30)

This is similar to the design of Aeromotive's Stealth fuel cells, except that they use a window near the bottom of one of the walls instead of the "maze" opening. You can't really tell from this drawing (Aeromotive Steath Cell), but the window would be located right behind the fuel pump pick up. The tube on the right is obviously for the return so it has just a low-walled baffel.

68lsxc10

iTrader: (1)

No, my tank is no longer behind the seat. I built one to mount under the bed. I had looked at a lot of aftermarket tanks, but you could see them hanging below the bumper from behind. So, I built my own, and you cannot see it from behind the truck. it holds approx. 21 gallons

68lsxc10

iTrader: (1)

Its been about three years since I built it, but I think the maze is about six inches high. I also placed two dividers into the tank to baffle it. (creating three equal sized chambers) I just cut the four corners off of the baffles to allow fuel to flow between the chambers. Although the truck is not any kind of race vehicle, with the tank mounted behind the rear axle, I wanted to minimize weight transfer from fuel slosh in a hard corner.
By the way, I ran it at the dragstrip one time and it ran 12.83 in the 1/4.

TurboS10

iTrader: (12)

I don't know how many hrs I've spent trying to figure something out for this.
Excellent idea.

If you don't want to weld on the tanks. Use marine epoxy to seal the a plate up bigger than the hole you cut.

TurboS10

iTrader: (12)

Something I found while looking for something else of course....

http://www.tanksinc.com/index.cfm/pa...=cat/cat61.htm

claytonisbob

iTrader: (1)

I thought about the tanks inc thing. But $225 would be nice to not have to spend. I mildly based my idea around their design, but I didn't know how well the single hole at the rear of the sump would work.

Another thought; I'd need some bulkhead fittings. I know there is some AN stuff, but really none of my fuel system will be AN, I'm just using 45 degree flared steel line. I wonder if there are bulkhead fittings similar to the ones Tanks Inc uses. Like a 90 degree elbow 3/8" fitting with either a barb on both sides, or threaded for a female 45 degree flare. I've seen 90 degree hose barbs, but Id have to find a way to seal it. I may just try to get it all working with the factory sending unit. I know a lot of people use AN with rubber hoses, aluminum, or stainless, but I don't know why regular ol 3/8" steel line is so bad that I never hear about anyone using it. It may rust over time, but I'd think it would be better than rubber which fuel deteriorates pretty quickly (aside from pricey Teflon lined stuff). Plus I have a tool to flare steel line, not stainless.