School me on aux tank plumbing (2 Viewers)

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cbmontgo

cbmontgo

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I am removing my auxiliary tank so that I can clean it and replumb it with new fuel lines. The aux tank fuel line goes above the tranny to a valve of some sort that I can't seem to get to.

On top of the tranny hump, there is a fuel selector switch for "main" and "aux" tanks. I assume that the main tank is plumbed into this same valve and then goes to the engine.

My question is, are these fuel tank selector valves typically manually-driven or are they electric? If I could get to the damn thing, I could easily figure this out.
 
they probably make both manual and electric, but if it is a switch and not a pull type knob, then it would be electrical. I use one from jc whitney that switches between tanks. Some people have used "transfer" small pumps to send the gas from one tank to the other. I think the switching valve is a much better solution.

Noah
 
It is hard as hell to turn the switch though, which almost makes me think that it is turning a manual valve?

Anyone got a diagram what one of these valves looks like?
 
An electric switching valve should have a normal on-off-on switch usually mounted on the dash. The manual ones are generally mounted on the floor directly to the switching valve and would turn from tank-off-othertank. Sounds like you have a manual valve.

The electric ones look like this
http://pollak.thomasnet.com/category/fuel-tank-selector-valves
 
60fj25 said:
An electric switching valve should have a normal on-off-on switch usually mounted on the dash. The manual ones are generally mounted on the floor directly to the switching valve and would turn from tank-off-othertank. Sounds like you have a manual valve.

The electric ones look like this
Fuel Tank Selector Valves on Pollak
Click to expand...

Thanks. In that case, mine must be manual.

I may just leave it where it is and only replace the fuel lines.

The weird thing is that the PO said that the fuel tank gauge will move towards "full" when the tank is switched to auxiliary. Why would this be? I don't think the aux tank has a fuel sender.

Also, what is the ID size for stock fuel lines on a '76?
 
I think you may have a manual valve
Does the selector switch look like the top of this valve?
56223.jpg
 
I had one hooked up in my cruiser, but I replaced it with the Pollak electric.

Brass 3 Way Fuel Selector Valve

They are kinda hard to turn, you can unscrew thoes two flats and dismantle it completely, it's just a tapered plug inside that switches the inlets. If the top cover is tightened too much it will make it very hard to turn, you can loosen it a bit, but might cause leaks.

Maybe your auxillary tank is plumbed as a feed tank, where it feeds back to the main tank? Seems like the fuel would move the other way though.

On my 75, the stock input line was 3/8.
 
ducktapeguy said:
I had one hooked up in my cruiser, but I replaced it with the Pollak electric.

Brass 3 Way Fuel Selector Valve

They are kinda hard to turn, you can unscrew thoes two flats and dismantle it completely, it's just a tapered plug inside that switches the inlets. If the top cover is tightened too much it will make it very hard to turn, you can loosen it a bit, but might cause leaks.

Maybe your auxillary tank is plumbed as a feed tank, where it feeds back to the main tank? Seems like the fuel would move the other way though.

On my 75, the stock input line was 3/8.
Click to expand...

Thanks...it looks like it comes in either 3/8" or 1/4" sizes and is connected to the fuel lines via male brass adapters with barbed fittings. Definitely not electric. That is good news for what I am looking to do.

I am going to get under the 40 and see what it looks like. This thread has been a huge help.
 
cbmontgo said:
Thanks...it looks like it comes in either 3/8" or 1/4" sizes and is connected to the fuel lines via male brass adapters with barbed fittings. Definitely not electric. That is good news for what I am looking to do.

I am going to get under the 40 and see what it looks like. This thread has been a huge help.
Click to expand...

I thought standard rubber fuel line was 5/16 ???

With an electric switch, there should be a way to have an aux tank sender too, right? Presently, only my main tank under my passenger seat, registers on my fuel gauge. I eventually want to use my aux tank too, but I'd like to put in a fuel sender in that aux tank and hopefully have it switch over too, along with the fuel lines. Is that too much to ask?

How specific or difficult are fuel senders? I think my aux tank is a custom aluminum? Can anyone tell? Are the sender units hard to install? Are they tank-specific?
608421627_KKUvE-M.jpg
 
Although it looks custom... It is very similar to the old confer units. I just finished mounting a stock landcruiser fuel sender in mine. I'll have a look for the thread where I got pointers. If it is similar in depth to the stock tank you should get fairly accurate results. Mine was a perfect fit.
 
Hey, Bikesmurf, did you end up adding any length to the float arm? Or did you just run it as is? I am wondering if I need to use the, evaporation(?) lines, you know those three extra lines coming from the stock tank location. Where did you mount your filler neck? I was hoping I could use the stock location...
 
I've not installed the tank yet. There are tones of pictures of MAF and confer tanks on the web. From what I've read you want to mount it as high as you can so that the auto shutoffs on the pumps will let you fill it.

I didn't add anything to the float arm. It nearly reached the bottom and I'm happy to know roughly how much fuel I have in there.
 
bikersmurf said:
I've not installed the tank yet. There are tones of pictures of MAF and confer tanks on the web. From what I've read you want to mount it as high as you can so that the auto shutoffs on the pumps will let you fill it.

I didn't add anything to the float arm. It nearly reached the bottom and I'm happy to know roughly how much fuel I have in there.
Click to expand...

This link/thread is awesome! :beer:

I'll take some pics and measurements to see if this is a custom of MAF/Confer tank and post here. Maybe I'll drop the tank to add a sender unit when I clean it out and replace the bad fuel lines. Thanks!
 
bikersmurf said:
I'

I didn't add anything to the float arm. It nearly reached the bottom and I'm happy to know roughly how much fuel I have in there.
Click to expand...

That's about all I expect of the stock guage and sender in the stock tank as well.;)
 
All righty guys, I am finally to the point where I about to put in my aux tank, probablly next weekend, and convert it over to my primary tank. Two questions,

1. Will the existing fuel pump be sufficient still, or do I need to upgrade to a more powerful one, perhaphs even an electric one?

2. Fuel lines, will an extension be fine, or do I need to have solid length lines, and should they be stainless or rubber?
 
imabigbangkindaguy said:
All righty guys, I am finally to the point where I about to put in my aux tank, probablly next weekend, and convert it over to my primary tank. Two questions,

1. Will the existing fuel pump be sufficient still, or do I need to upgrade to a more powerful one, perhaphs even an electric one?

2. Fuel lines, will an extension be fine, or do I need to have solid length lines, and should they be stainless or rubber?
Click to expand...


OE pump ok. Metal extension with brake line.
 
bikersmurf said:
https://forum.ih8mud.com/40-55-series-tech/267066-where-put-fuel-sender-maf-aux-tank.html

There are some instructions there. It should work if your tank is near 10" deep. If not I'd modify the stops/sender to make it work. :)
Click to expand...

That link is awesome. VERY informative. I can't seem to find too much specific info here or on Google, on how to actually install a fuel sender in a custom tank that does not have a precut hole. I've seen some posts about leaking gas problems and difficulty getting a good seal. Is this true?

My aux tank I think is custom. Only about 7" at all 6 points. Here's a pic, and a quick not-to-scale diagram I made with measurements. My rough math estimates about 17GAL, which seems a bit smaller than most aux tanks I hear about (22-26gal or more?) Can anyone check my rough specs and see if I'm right?
608421627_KKUvE-M.jpg

923524194_jRfW3-L.jpg


I'm wondering how difficult it is to drill a hole and install a universal sender unit? Where best to get this unit? I think Jegs and SummitRacing both have it. What would be the best location? I guessed at 2 possible sender sites on my diagram. There is a slight down tilt towards the back, at the fuel line insertion point.

Finally, what would be the best way to connect new line to this? I'd like to use 3/8 brake line, as recommended by many here, but I'm not sure how to make this connection:
923516415_BtmkP-L.jpg


On another related thread, I asked about these brackets that held the hard fuel line against the frame. The brackets had some rubber lining, and screwed into the frame? Any idea what this is, or what is best to use to run and secure the hard fuel line from the back of the rig up towards the front?

Ok.. thanks. :beer:
 
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