Is there a knack to filling with petrol?

[john.p.clegg]

..are not the two vents part of the tank design?

John

[rgh0]

The problem with plus 2 filling is not the adequacy of the vents but the fact that the fill pipe goes into the tank halfway up. Once the bulk fuel in the tank covers the fuel filler inlet to the tank then the fuel backs up and foams in the filler pipe as you fill shutting of the fill nozzle automatic cut out.

Normal fuel tanks fill from the top so the fuel in the fill pipe drops out into the tank and you have a large surface area to disengage the foam. The tank during filling can also then vent back up the fill pipe as well as through the tank vents

No easy fix for that except pull the nozzle out a little and fill more slowly to prevent the foaming.

Sealing the cap so a full tank does not slop and leak out onto the paint is another separate challenge

cheers
Rohan

[tcsoar]

Hi Guys,

Agree with Rohan on this one (no surprise there). I have the original set up on mine but have fitted two short lengths of 15mm copper tube to either end under the car and these are fitted with plumbers push fit stop end fittings, one has a small 1mm hole drilled for venting while driving if I forget to take one off. Filling a tank is achieved by taking both stop ends off and filling normally until it auto shuts off, then lifting the fuel nozzle up and filling slowly the last half tank.
Also had the petrol slopping down the wing with a full tank. Sealed the breather hole which worked for about a year then the problem came back. Careful inspection, and the fact that it was getting harder to unlock the cap, revealed the petrol had washed out any grease in the lock and was now exiting through the lock. Changed to unlocked cap, problem solved.

Chris.

[Robbie693]

I usually only put in 40 litres as that is what the additive I use should be diluted to but I find the fuel starts backing up the neck after about 30-odd litres.

I find putting the nozzle against the wall of the filler pipe enables a smoother, less frothy fill which minimises cut-outs at the pump. Rather like pouring a beer into a glass to minimise the head!

[bill griffiths]

Thanks for the help.
I rather expect that modern tanks do not fill from half way down the tank either! I remain unconvinced that it is anything but a venting issue. I do not know what the reference to the nozzle means; we have only just got the talkies here, but even being filled from a bucket would meet with the same issue.
Perhaps if there is insufficient venting, pressure may build up resulting in fuel spilling on the guard.
I shall persevere with my plan but add the Mazda component as well.
Regards,
Bill

[Lotus 50]

I have to fill mine very slowly to get it to be really full. And then it spills over the fenders when I corner. My solution for the spill is plastic wrap (I think it's called cling wrap in the UK), which works fine. Patience works for filling.

The other bit of fun is that the low fuel light comes on when the gage reads just under 1/2 tank, and the low fuel light unlike the gage must be believed.

Minor nuisances.