Vixen Fuel cap

[jpa]

Hi,

I recently had a problem where on a hot day I noticed fuel trickling from my fuel cap. When I popped the catch, the cap flew open and I had a wonderful fuel fountain effect going on where about 1/2 litre spewed out. The fuel sat right at the top of the filler neck for a few moments before gurgling back down into the tank.

I assume that the tank is fairly full (my gauge lies a bit) and that the warmth had built up vapours in the tank with nowhere to go.

The question is, should the cap have a vent of some sort? I cannot see anything obvious. There is of course the small pipe that connects the bottom of the filler neck and goes back into the tank but I cannot see that this would do anything about the situation I had unless there is some small vent hole on the cap.

Can anyone help?

[THREEFISHORANGE]

It should have a breather near the top to stop this happening. Is it the original tank, or has it been reproduced??

[jpa]

I think it is original. The tank does have a small pipe that goes from the top of the 'end' of the tank, near to the filler neck exit on the tank, that goes into the neck of the tank at about the same level. I cannot see how this would allow vapour to escape.

What I am asking is, should there not be a vent on the cap itself to allow the tank to breathe?

[THREEFISHORANGE]

It could possibly be that the seal is sealing on the neck/filler which is right,but the cap itself may be blocked(it would only be like a pin hole)? If you buy say an ASTON style cap. they have the breather incorporated within the cap.
Hope this helps.

[jpa]

Thanks for that. I have the original aston style flip cap but could not find a vent hole. I will check again as it must be blocked.

[Loubaruch]

jpa said:

I think it is original. The tank does have a small pipe that goes from the top of the 'end' of the tank, near to the filler neck exit on the tank, that goes into the neck of the tank at about the same level. I cannot see how this would allow vapour to escape.

What I am asking is, should there not be a vent on the cap itself to allow the tank to breathe?

Not sure if my 1972 1600M has the same arrangement as the Vixen but the 1600M has 2 small pipes terminating in a T piece. One pipe to the filler neck the second to the fuel tank vent pipe. The third arm of the T has a pipe that pokes down and out of the body. Presumably this allows both the tank to vent and any overfill to either drain back to the tank or spill out under the car. Seems to work OK.