Fuel Tanks & Mods

[Kinarfi]

Just got my new fuel tank in, wow, what a long filler neck , I guess things do improve with age, no wait, it's the newer the better, oh I just don't know, guess it really doesn't matter. Take a look at the photos, , just for fun, I'm going to design & build a capacitive fuel gauge sender for it and make mod similar to flatbed's so the engine doesn't die when going down hill with low fuel. I'll take more photos

[rocmoc]

Nice pics. Looked at the entire album.

rocmoc n AZ/Mexico

[Kinarfi]

Pulled the old tank & took the fuel gauge apart to see what makes it tick. It turns out that it has 5 reading, empty for the last 2 inches, 1/4 for about 1 1/2 inches, 1/2 for about 1 1/2 inches, 3/4 for about 1 1/2 inches and full for about 2 inches. Some other detail are: when full the resistance is 3 ohms and .3 volts when empty it has 110 ohms and 4.6 volts. It is grounded internally, poorly in my opinion, mine had started leaking if I stacked the tank, so I epoxied it to seal it up.

As the gas level rises, a magnet floats up closing the reed switches, there is a stop for the float about 3/4 inch from full.

[rocmoc]

My sending unit stopped working a couple of months ago. Joyner would not replace but would sale me a new one, but only guaranty the new one for a month. The thing cost nearly $90. I said forget it. My dealer tried to repair and did sort of. Since I have a front hood that opens, I am installing a simple sight gauge or replacing with a simple sending unit with a float arm. I know of a couple other people who's gas gauges don't work. Personally this is one item that I would call over built/engineered and a piece of junk.

rocmoc n AZ/Mexico

[Kinarfi]

Mail it to me and if I can, I'll fix, shipping charges only. I enjoy messing with things like this and if I get my capacitive fuel gauge working, I'll build some extra ones. PM me for my address if you want to do this.

Jeff

[rocmoc]

Sending you PM.

THANKS!

rocmoc n AZ/Mexico

[flatbed]

kinarfi, if you look at the tank that i change you will see that i moved the mounts closer to the edges of the tank, if you hold the tank on the mounts closest to the filler spout the tank will balance on those two tabs, that means those two tabs are holding all the weight and the others are balancing the tank. Move the tabs to the end of the big part of the tank and make sure you put rubber on the mounts.

[Kinarfi]

Will do on the rubber mounts, but I think I'll run the stock mounts and monitor them until the break and then have the sturdy L bracket like your's welded on.

Thanks

Jeff

[rocmoc]

Be careful welding on a gas tank. Have done it but didn't like it. Even if it is empty, it can explode.

rocmoc n AZ/Mexico

[Kinarfi]

Be careful welding on a gas tank. Have done it but didn't like it. Even if it is empty, it can explode.

rocmoc n AZ/Mexico

I always fill it with water, but not wet the area being soldered/welded and then ignite any vapors prior to starting. At worst, you may get a small woosh as you burn off what ever vapor is left, and since it is controlled and expected, it is relatively safe. If memory serves me, 1 gal gas, properly mixed with air, is equal to 8 sticks of dynamite.

Thanks,

Jeff

[flatbed]

Kinarfi, I am thinking you will be sorry if you do not move the one set of tabs rearward on the fuel tank, with the added resiviour and the longer filler neck it is almost certain to break. Also you can fill the tank with carbon deoxside while welding, that is what i did. Keep the bottle on it with very low flow and little preassure.

[Kinarfi]

Got my fuel tank in and mounted, , mounted it on 6 rubber standoffs and it seems good, had to stop the seat 1/4" from all the way back because the 1" lift made the filler neck hit the back of seat. Will run a ground wire from frame to tank tomorrow, may add a new fuel pickup line later.

[Kinarfi]

My sending unit stopped working a couple of months ago. Joyner would not replace but would sale me a new one, but only guaranty the new one for a month. The thing cost nearly $90. I said forget it. My dealer tried to repair and did sort of. Since I have a front hood that opens, I am installing a simple sight gauge or replacing with a simple sending unit with a float arm. I know of a couple other people who's gas gauges don't work. Personally this is one item that I would call over built/engineered and a piece of junk.

rocmoc n AZ/Mexico

I've been working on Rocmoc's gas gauge sender unit, waiting a part, and drew up the schematic for the Troopers with a front gas tank. Not to be disagreeable, but these things are very simple in their design and construction. Their biggest problem, IMO, is the red seal where the wires come out. The under seat gauges indicate by 1/4s and front tanks indicate by 1/8s.

[rocmoc]

I defer to you. This is not my area of expertise. I am just old school with a float, arm and a resistor kind of guy.

rocmoc n Mexico/AZ

[Kinarfi]

I defer to you. This is not my area of expertise. I am just old school with a float, arm and a resistor kind of guy.

rocmoc n Mexico/AZ

Your's is fixed and boxed and will be coming back home tomorrow, or is it monyawna, since your in Mexico right now?

[Kinarfi]

I was talking to turbodude, Scott of Unleashed Motor Sports about gas tanks and he mentioned to me that the new tanks have a baffle in them between the gauge / filler pipe area and the rest of the tank, so I looked and of course, he's right. Interesting IMO. And since I couldn't stick my head in to look at the baffle, I stuck my camera lens in through the fuel gauge hole.

More photos at http://s481.photobucket.com/albums/rr180/Kinarfi/

Played around with photobucket and think I like webshots better, just my opinion.

[Kinarfi]

Well damn, I have been building a clunk pick up for my Trooper's new gas tank and finally got around to cutting a hole to put the clunk in, I found another baffle in the middle of the tank, defeating my idea. Now I have to clean the metal out of the tank and patch the hole.

I have another idea though, and it should be easy build once I find something that will work as a float. Basically, it's an upside down carb float, when gas is present, the float holds the needle valve open, when you head down a steep hill or up, and all the gas moves to forward part of the tank and uncovers the outlet, there is no gas to hold the float up and the needle valve closes and the fuel pump has to pull fuel from the new front pickup which also has this setup. Ideally, you should not run out of gas going up or down when you're nearly empty.

Any input, anybody?

Jeff

[flatbed]

sounds good, just make sure it don"t beat it self to death. I have not had any problems since moving my sump to the middle.

[Guest Lenny]

I heard something rattling. Sounded just like a loose tank would. Sure enough, 3 of 4 tabs were broken and the last ready to go. To correct the problem I decided to put a 3/8" peice of plywood with tabs to prevent it from moving under the tank with about a 3/4" layer of polyethylene foam. I then put long threaded studs through the frames tank mount holes and bolted them in leaving mounted threaded studs sticking up. I then made some good solid straps to go over the tanks top. As I tighten it down the foam compresses and provides a solid non moving tank. This was pretty easy and makes for another solution that avoids welding for those that don't have the welder. I could have welded it but I was lazy. I was thinking, gosh, I got to drain the tank, pull all the fittings loose, make provisions so I don't blow myself and the tank up, redo it all and get things reprimed for starting. It was getting late and that sounded like a lot of work.

they quit showing fotos

You will also notice that I put little tabs on my seat belt eye bolts. This keeps the metal clip out of from under the seat when it's being closed. I just pull up on the straps when closing and the rest of the belt stays out to. Before the metal clips would fall down around the eye bolt and not clear always when pulling the straps up.



Lenny

[Kinarfi]

I like your straps, Plywood and foam under, when I replaced mine, I did quite a bit of hammering to take out some dents, but with the plywood resting on the frame, I think your set. That's kinda what I was going to do while I waited for my new tank, but then I just padded around and under it.

I like your seat belt anchors too.

Jeff

[Kinarfi]

Some assumptions for easy calculations, The gas tank is 19.5 front to back, and 7.0 deep, width does not apply.

Starting at 1/2 full, 3.5 inches of gas, as you go down hill at an angle of 19.75 degrees or more, your fuel outlet will uncover and your engine will die. As your fuel level decreases, the down hill angle decreases at which you'll run out of gas. It may take a minute or so but if it's a long hill or the pace slow, you'll run out of gas, I have, on 3 different occasions, once while one a dirt road when my fuel was less than 1/2, maybe a 1/4 or 1.75 inches.

Inches of Fuel---- Incline---TANK

0.25 --------------- 1.47

0.50 --------------- 2.94

0.75 --------------- 4.40

1.00 --------------- 5.86

1.25 --------------- 7.31

1.50 --------------- 8.75

1.75 --------------- 10.18---1/4 FULL

2.00 --------------- 11.59

2.25 --------------- 12.99

2.50 --------------- 14.38

2.75 --------------- 15.75

3.00 --------------- 17.10

3.25 --------------- 18.43

3.50 --------------- 19.75---1/2 FULL

[Kinarfi]

Occam's razor is often paraphrased as "All other things being equal, the simplest solution is the best."

I think my running out of fuel solution will be to have a hose from the front of the tank, a hose from the back of the tank, a hose from the fuel return and a hose to the pump all meet at a point under the gas tank. My thinking: if the engine needs 10 units of gas to run, the pump pulls 100 units from junction, the return line returns 90 units and the unpressurized lines from the tank flow 15 each, as long as the junction is lower than the gas level, the pump can't suck air from the uncovered outlet. This is very similar to Flatbed's solution, but no welding and the gas flows out side the tank. No valves, no moving parts, just gravity and gas flow, simple.

Jeff

[Guest Lenny]

I think you might be on to something. As I think about mechanical solutions, they seem to stay complicated. Your in effect creating a low gas point that is lower than any part of the tank and will always draw off where ever the gas is available. Like it, nothing mechanical to foul things up. I think that is the way I'm going to do mine. Good thinking and keep up the good work.

Lenny

[Guest Lenny]

Well, after my last post here, I went to take my after lunch 30 min. power nap. I really don't get any new power but If I'm lucky, I get to brainstorm a little during this time. I cut todays nap short as, thanks to Kinarfi, I couldn't stop thinking about his lower collection point tank idea. I kept picturing the trooper being on a 45 degree slope coupled with where the pickup would need to be to still be below the tanks gas level. That kept putting it somewhere inbetween the bottom plates and the ground. Not good. However I think I have got the answer. I don't have time do show you right now but will later this evening when I'll have time to do a couple of sketches I can post. Actually I'm not upset with Kinarif because of my nap time. He got me thinking and I got excited and well, I couldn't sleep anymore.

Later

Lenny

[Kinarfi]

aint it FUN, not as fun as testing the final version by going riding, but fun when you have 18" snow outside. All you need is to have junction below the level of the top of the gas. The only place I can see a short coming compared to stock, is going up steep hills with low gas, like on your way home after a long, hard day, Stock, all fuel to the rear for easy pick up, Modified, depending on where the junction is mounted, you'll run out of fuel while you still have some, not much though. At present, with tank raised 3/4" - 1" on rubber mounts, (REVISED) I plan to buy a cross and screw in some 5/16" barb fittings and then wrap it with some kind of foam. Easier than what I said before.

Damn, your wordyness is catching. Photos when I get it going.

Jeff

[Guest Lenny]

I think my solution will eliminate your concern with running out of gas on an uphill when low. I've included a drawing (side view) that was drawn sort of quickly but I think you can get the idea. Picture your tank being raised so there is 2" below it. Put an outlet at the front bottom of the tank and use the existing rear outlet. Centered under the tank is a 2" OD by 1 3/4" ID pipe, probably steel as we want it to take a hit from the underside. This pipe is 15" long. The outlet from the front of the tank goes to the rear inlet on the pipe. The outlet from the rear of the tank goes to the front inlet on the pipe. These pipe inlets are kept as high on the pipe as possible. Maybe just one inlet at the top of the pipe at the end putting the end past the edge of the tank. Both lines from the tank could merge and go into this one inlet. The outlet on the pipe comes in from the side and 90s down to the pipe bottom. We want to come in from the side to keep the outlet away from bottom hits.

If you look at the drawing straight on, the gas fills the pipe when level. This happening should be very reliable. Now take the sketch and tip it 45 degrees as if going down a very steep hill. With the inlets on the pipe being at or near the top, only a small protion of the collected gas can go back to the tank. Look at the inside area of the pipe marked "A". Actually the top line of area "A" should be just under the left pipe inlet which connects to the front of the tank. This would be the gas available to the engine while on the 45 degree downhill. The same principal works from the opposit direction when going 45 degrees uphill.

That said, a 1 3/4" ID pipe has 2.4 square inches of cross sectional area. Lets assume that we can retain at least 1 square inch of that area of gas. I think we will retain a lot more then that. That 1 sq inch times 15 inches of pipe gives us 15 cubic inches of gas. A gallon is 232 cu in. Our 15 cu in of gas is about 6.5% of a gallon. If your getting 15 mpg say, that means there should be enough gas in the pipe to go just under a mile. Now, if your on a hill that is 45 degrees for a mile, you deserve to run out of gas. As a matter of fact, you should have your trooper confiscated.

Everybody jump in with your concerns and possible changes.

Sorry Kinarfi, I didn't get around to learning to post the pictures correctly yet. That's OK I'll help

Lenny

[Kinarfi]

I think you'll get more fuel than you figured, as soon as either tank out let uncovers, the fuel in the hose drains through the pipe until the extended line of the top of the gas level gets to the uphill inlet of the pipe and that is when you begin driving on pipe gas. And in my illustration, at 45 degrees, you have been running on pipe gas for just a few degrees at a !/4 tank and if the pipe was lower / smaller, you may still be on tank gas at 45 and 1/4 full. But then you should be at home or camp with that little fuel too.

Jeff

[flatbed]

The way the tabs are put on the tanks it makes it so the back 2 hold all the weight, the others just balance it. The back 2 tabs need to be moved rearward. On the hose idea for fuel tanks they make a check valve that is inline, where the weight of the ball closes the line. one on each end ofthe tank would solve yourproblem.

[flatbed]

Now you got me thinking, you could also just put in a manual valve for 2 tanks. they are normally 3 postion. swith it to one side of the tank for step hills depending on weither you are going up or down and in the middle for normal crusing. that would be pretty simple to do

[Guest Lenny]

The way the tabs are put on the tanks it makes it so the back 2 hold all the weight, the others just balance it. The back 2 tabs need to be moved rearward. On the hose idea for fuel tanks they make a check valve that is inline, where the weight of the ball closes the line. one on each end ofthe tank would solve yourproblem.

I have some concerns about using a double check valve. Today, I put together a simple double check valve with some fittings I had around. It is set up so that a free moving steel ball is at each end of the assembly. Each ball can roll to it's respective outter end of the assembly and past the gas flow area through that side so the gas flow doesn't suck in closed. I can tip the assembly down on either end causing gravity on the ball to close the input on the opposit end. It takes very little slope to cause the balls to roll. If I'm correct, shuttle valves are designed to route the input side of the flow that has pressure on it to the outlet. In other words, you can turn a pump on from one source and the shuttle valve sences the pressure and shifts to receive product from that side or from the other side if it is the input with the pressure. It's a either-or setup. In our case the input lines are not pressurized but instead, the outlet side is sucking. When I suck on the outlet (middle fitting), I can tip the assembly causing the balls to roll and open/close their respective sources. It takes very little slope to cause this to happen. Where the problem comes is, with continous light sucking, I can tip the valve from one side to the other side and the other ball closes its source but because the suction is continous, the first ball stays sucked against its seat. This ball will stay there even when I tipe the assembly 45 degrees. In other words, both sides are shut off to gas flow.

Am I missing something. Lets here some thoughts.

After looking at this, I can see the possibility of both sides being closed at the same time. I think I abandoned it, but not sure.

Lenny