Filler Cap Breather Hole

[William2]

I have just bought a new locking fuel filler cap to fit to my S4 Elan and would like to find out whether it is necessary to drill a small hole somewhere in the cap to act as a tank breather or not?

[types26/36]

Not if it is like this, doesn't yours have a hole here?

[john.p.clegg]

Brian

Are you going to open out that split pin a little?

John

William

Is a breather needed (just for the filler tube) or doesn't the B**y elan not have the large breather tubes?

John

[types26/36]

Brian

Are you going to open out that split pin a little?:

No John, not for the moment, I need to sort a key out for it so it has to come apart again (the legs are slightly apart although the pic dosent really show it)

[TroonSprint]

I am also wondering about the tank cap vent. I have bought a new locking cap from Mattys and haven't noticed any sort of vent. The 2-seat Elan has no other tank breathers.

Mike

[William2]

I am waiting to receive the filler cap in the post. The pictures I have seen of it on Ebay did not seem to show a breather hole so I will confirm when I receive it. Thanks for your comments, William.

[alan.barker]

where the locking part turns in the middle it's not airtight, so no problem. I have a locking cap on my baby elan

[billwill]

Reminder:

PLUS 2 cars already have built in breathers, the cap does not need to breathe.
ELANs (two seater cars) do need a breather hole in the fuel cap.

[fatboyoz]

William,
When I bought my S4 (1987 in Hong Kong), one of the previous owners had removed the filler, bogged up the hole and used a VW filler neck and cap inside the boot. Fortunately, when I picked all of the bog out of the hole, the hole, and profile where intact and did not require repairing.
I purchased a new filler neck, seal and locking cap for the restoration. I can tell you now, that they seal very well. The first couple of tankfuls, after the car was back on the road, the cap was difficult to open due to a vacuum in the tank. The fuel tank was also oilcanning due to this vacuum.
On investigation, I found that the breather hole, as shown in Brian's post was only drilled on one side. There is a annular void moulded into the cap with holes drilled in each side, 180 degrees apart, or there should be. I had to disassemble the cap to drill the extra hole. This after speaking to the manufacturer.
Possibly worthwhile giving the hole a suck, just to be sure that all is in order.
Cheers,
Colin.

I have just bought a new locking fuel filler cap to fit to my S4 Elan and would like to find out whether it is necessary to drill a small hole somewhere in the cap to act as a tank breather or not?

[William2]

Thanks for your help. I have drilled a small hole in the cap where indicated just in case of vacuum problems.

[TroonSprint]

On investigation, my new locking cap from Matty's already has a tiny breather hole on both sides of the metal plate, so it shouldn't be a problem.

Mike