3 litre fuel tank

DavidThompson · Posted: Mon Jul 06, 2020 2:53 pm Post subject: 3 litre fuel tank

Just in case it is of any interest to anyone on this forum :
50 litres of fuel in a standard tank rises to 10 3/4 inches.
40 to 8 3/8
30 to 6 1/4
20 to 4 3/8
10 to 2 1/2

Philip Edginton · Posted: Mon Jul 06, 2020 7:38 pm Post subject:

Can we have measurements of weight as well please.

John Murch · Posted: Mon Jul 06, 2020 8:19 pm Post subject:

A litre of petrol weighs roughly 750gms..........
The weight of the fuel tank empty, I have no idea!

Interesting, I would have thought that the 30 - 40 and 40 - 50 litre increment would have been greater as the tank slopes back towards the top.

At least you can put a dip stick into a 3ltr tank, matters are more difficult with a 4 1/2 tank (although you should have the benefit of a gauge).

DavidThompson · Posted: Tue Jul 07, 2020 1:58 pm Post subject:

Yes, you would have thought so.
The tank top slopes back but the filler neck is more than half way down the slope. 50 litres comes to about half an inch below the lower side of the filler, so not much of the actual fuel cavity is affected by the shape of the tank. The last 10 litres takes up slightly more vertical space than the preceding 10 litres, as you would expect.
However, I offer no guarantee as to the absolute accuracy of my figures, but calibrating the dip stick provides more idea than simply knowing there is some fuel in or not.

John Murch · Posted: Tue Jul 07, 2020 3:47 pm Post subject:

I had my fuel tank (which had obviously been replaced at some point as it's aluminium) extended a bit like the 4 1/2, so it now holds about 75lts. (I found that when touring in remote regions I suffered range anxiety) Recently someone seems to have reversed into it with a tow bar, the cost of repair or replacement is horrific, fortunately the insurers have accepted the claim.
My intention is to make up a calibrated stick, but how do you get to the garage forecourt totally out of fuel? Drain it at home, put in 5ltrs then a drive to the garage at a quiet time?

DavidThompson · Posted: Tue Jul 07, 2020 5:27 pm Post subject:

I filled a 20 litre can, then dispensed it into an empty tank. I then dipped and marked, took the car to a nearby petrol station and added 30 litres, stopping and marking at each ten. Clearly it is out by the distance to the petrol station - about 1.5 miles - but in the grand scheme of things didn't think this too important.
I had thought to look out for a 4.5 tank, it not having occurred to me to enlarge the one already fitted. In the meantime I have fitted a 20 litre can and holder to the nearside running board.
Modifying the existing tank might be a better way to go, but sounds expensive.

John Murch · Posted: Tue Jul 07, 2020 7:11 pm Post subject:

I think the original tanks are steel plated with something else, lead? This may make welding problematic, the 4 1/2 tanks have different mountings and a different filler arrangement, I rather like the 3ltr arrangement.
Just getting the old tank out is not a quick job, the rear spring hangers have to be disconnected etc. Etc...
Having been though the process I can confirm that it was far more expensive than I anticipated, so 20ltrs of fuel cans sounds an excellent solution.