No Fuel Guage ?

[hmalan]

I have one of the fire extinguisher type fuel tanks.

I know that once it is built I could fill the tank, run the car until it is empty and then see what mileage it has covered.

Then set the odometer to zero each time I use it and make sure that I top up before I get close to this figure.

Is there a better way ?

Would the rod type sender that ESDEBE hd built into his tank work with a fire extinguisher type tank

All advice appreciated

Regards

Alan

 

[jerry]

Hi,
The standard type mini fuel tank sender can be made to fit a fire extinguisher. i did it on my first buggy. cut out the mounting hole from the doner tank, cut a suitable hole on the extinguisher about a third of the way up, shorten the float arm to the width of the tank. weld the mounting to the new tank, fit the sender unit, and it will show full on the gauge till about half full, drop to empty on the gauge when there is around quater of a tank left, leaving you with about 2.5 litres of fuel.
worked really well and was reliable.

Jerry

 

[esdebe]

Another option if you just want to knwo when it is getting empty (a warning lamp) is to use a float switch like

http://www.maplin.co.uk/Module.aspx?ModuleNo=12167

This requires a small 17mm hole to be made, then you drop it in to the tank fish the wires though the hole, and tighten up the nut on the outside, it will then allow you to turn a light on / off when the level drops...

I'm usng one of these to turn of a fuel pump that transfers petrol between tanks then my main tank is full again.

I'm also using a small fluid level sensor from RS components

http://rswww.com/cgi-bin/bv/rswww/searc ... uknetscape

this requires a buffer circuit to amplify the signal, but I use it to tell me when the reserve tank is empty, and to cut off the pump.

 

[hmalan]

Esdebe,

This looks really interesting but your technical knowledge is obviously way above mine as I do not understand what you mean by "buffer", a buffer to me is what we have on trains.

I would be quite happy if I could fit something in the tank that would illuminate a light when the fuel level had reached a specific level rather than needing a continuos read out.

Which of the two methods you have shown would be best for this ?

Many thanks

Alan

 

[Phaeton]

Simon,

I like the look of the Maplin float switch, in essence that is all I have on my Honda VTR1000, when the fuel gets low the light comes on in the instrument cluster. Did you have any problems sealing it into you cylinderical tank?

The other one looks a little complicated to me, have you seen the Demo of the float switches would this not do what you want in the slave tank DEMO to switch off the pump?

Alan...

 

[esdebe]

I found the optical switch first, at first I thought I would only need one sensor in the reserve tank that would turn off the pump when the tank was empty, however the more I thought about it the more I realised that I needed to put some slightly more intelegent circuitry in.

At the moment, when the car is turned on, the circuit I built checks the sensors in both tanks and if there ir fuel in the reserve and the main tank is below the level or the fill tank (I decided to have the reserve tank fill from the main tank so I only have one filler hole) the filler sensor is therefore below the level of the overflow pipe so I don't just pump it round in circles..

When the sensor in the main tank registers as full it activates a relay that breakes the circuit to the pump until a reset button is pressed or the iginition is turned on and off (orginaly it just turned the pump off, but if the petrol sloshed arround too much the pump would keep cutting in and out, not a problem for an LED, but a motor doesn't like this sort of start-stop) I may at some point put a second float switch in to do the reset automaticaly but I'm going to see how it goes as it may not need it and I have a guage in the main tank that tells me how full it is.


As for the buffer cuircuit, I wan't sure I just read that one was needed, did a bit or research (read google) and found that a simple transitor cuircut was all it needed then I though long and hard of my old GCSE technology course, but that didn't help.... and did some more google reserch to find a very basic cuircuit.


So far I have tested it all but only with water. I have only just got my reserve tank from the fabricator (it sits behind the drivers chair and adds an extra 15L capacity to the 10L cylindrical tank) I bought some tank repair (motorbike suppliers sell it to seal the inside of tanks) it is an epoxy resin that sets to form a pertol proof skin, I seal the fluid level sensors into the tank by painting some of this onto the threads before tightening up, and with the float sensor I just tightened it up, the sulphone washer squashes to form a lip on the inside and outside of the tank no leaks yet..... The curve of the tank is barely negligable compaired to the size or the hole that needs to be cut... If the curve is too much your tanks you could always use a hammer to create a flat spot.

 

[hmalan]

Jerry & Esdebe thanks for the responses which are helpful as ever.

I have ordered one of the float switches and will know doubt have further questions when it arrives.

Many thanks

Alan

 

[esdebe]

That demo is hypnotic. Just spent 5 mins watching the level go up and down and teh light come on and off... I hope I don't get as easily distracted in teh buggy when the lights I've riged to my tank go on and off... Then I don't thnik I can fill or empty the tanks that quick...

 

[Phaeton]

My tank has just started to leak from the float. It looks like The blue washer tthat came with my switch has started disintegrated & leak. Any thoughts on what it can be replaced with.

Alan...

 

[esdebe]

I did mention that to you at newark... Hence the other idea for the fuel sender....

I bought a mat of Nitrile Ruber, which is suposed to be fuel resistant, but even that seemed to desolve / expand.

I removed my float as I came up with an alternative using a reed switch inside my existing fuel sender.

However before I did this I took the maplin one, cur of the nylon flats on the nut so that it was round, I then took a brass tank fitting, and screwed this in place on the side of the tank (needed to enlarge the hole slightly. I also sealed the brass fitting to the tank with some chemical metal leak fix and then tightended the nut up on the tank fitting until the leak fix was squished out arround the edges (it takes about 15 mins for it to cure and go completly hard).


I then took a small length of 22mm copper pipe (about 1 inch) I put the float switch (with flats filed off into it) and filled the rest of the pipe and arround the switch with more leak fix. One thing you need to ensure is that the float swich is far enougth through the pipe so that when mounted in the tank connector it can still move. You then put an olive on the pipe and tighten with a normal pipe fitting (and in mycase a little more leak fix to ensure it doesn;t vibrate loose or leak.

I made my float switch, but never fitted it as I decided to use the other sender, so if you want I can bring you my converted float switch. You just need to buy a brass tank connector for 22mm pipe, and you can fit it with a blanking plate for now. I'll bring my float to the show on the 19th

see link for example of 22mm tank connector

http://www.edirectory.co.uk/pf/880/mia/ ... id/1418296

Simon

 

[Phaeton]

I did mention that to you at newark... Hence the other idea for the fuel sender....

I remember NOW that you've told me again. LOL

Got all the bits I need already apart from the chemical stuff, where'd you get it from?

Alan...

 

[esdebe]

any DIY shop, focus / B&Q or Halfords. It is in a yelow tubue and you mix it. You can use either leakfix or chemical metal.

It needs to say on the back that it is chemical and most fuel resistant.