Aero fuel filler (flap removal?)

[AntonyH]

Hi all,

As part of a wider car refurb I'm having an aero filler cap installed in place of the slightly grotty plastic one (2005 K-series - and every time I lock / unlock it I'm sure the key twists that little bit closer to snapping!).

I've read in some places that there's a flap internally that may cause "issues" with filling and some people recommend removing this - is that correct or now outdated info? Does the aero filler cause any filling problems? (Bearing in mind my normal filler already often forces pumps to click off every half litre **OR** not click off at all and therefore piddle unleaded down the back of the car if I'm not paying close attention).

[SM25T]

The flap is there for both metro style or aero filler cap. If the nozzle doesn't reach in far enough to open it, the auto shut off on trigger nozzle will constantly shut off when filling. Easy enough to remove the neck and knock the flap out.

[AntonyH]

Thanks - I'll chat with the refurber so this can be done before the filler is fitted.

[John Vine]

The flap is there (notionally) for safety reasons, in case you should have the misfortune to turn over (apparently).  A newly-built car without one would likely fail the old SVA (and the current IVA, I imagine).

Worth looking at this thread.  I removed my flap (and the supporting cone) as decribed in post #38.

I believe that the current aero cap may have a larger cut-out at 12 o'clock, which could mitigate the problem entirely (in that you can get the nozzle down far enough to open the flap).

JV

[martyn]

The flap has been removed from the filler neck in my car.  Every time I open the filler cap, fuel spirts and leaks out around the filler cap as the tank depressurises.  It then obviously runs down the paint and all over the rear light.

Is this a symptom of having the flap removed?  My thinking is that the flap must prevent fuel splashing up around the filler cap internals when driving.

I'm actually thinking about replacing the flap if it will fix this.  The previous owner removed the flap so I've got no comparison with how it behaves normally.

[SM25T]

The flap is not fuel tight. Have you got a one way valve on the small breather hose .... does it allow air in to the tank ?

[martyn]

I haven't really investigated it at all, so have no idea what it does or doesn't have.  I only thought of it and mentioned because I saw this thread.

Should there be a one-way valve?

[SM25T]

If you don't (mod as per CC tech bulletin) .... fuel runs out of breather hose on left hand bends.

[John Vine]

If you don't (mod as per CC tech bulletin) .... fuel runs out of breather hose on left hand bends.

Interesting.  I wasn't aware of that. 

I've just found the following (busted) link in here:

http://www.graduates.org.uk/racing/Fuel-tank-notice.pdf 

But this gives a 404.  Google came up with this PDF (WN371).  Is that the mod in question?

JV

 

[AntonyH]

I believe that the current aero cap may have a larger cut-out at 12 o'clock, which could mitigate the problem entirely (in that you can get the nozzle down far enough to open the flap).

Thanks John, and for the other posts, worth knowing.

[Dorset7]

I've recently fitted an aero filler on my car and I fill without issue. I used to have the same "spit back" on opening the cap on my old car and that had the flap removed. 

[john milner]

I have recently fitted a Caterham aero filler kit and it performs exactly as the Metro version did. i.e. perfectly once you have the knack.

 

I think the flap may be there to reduce petrol overflowing when a full tank is left in the sun and spillage if the cap is left off.

[Geoff Brown]

My 2013 kit came from the factory with an aero filler fitted as an option.....with no 'safety flap'......& the bonding lead not connected to the chassis!!!

Passed the IVA OK & I have had no issues with back leakage or filling once you know the correct angle at which to insert the nozzle.

[Nillbymouth]

I suspect that the aero filler design has changed. I had a look at mine at the weekend - a Supersport built last year with the aero filler included. There is no larger notch to go in the 12 o'clock position - there are 4 notches at 12, 3, 6, 9 and all are the same size. Also the flap is only about 1.5 inches from the cap - close enough that I can easily open it with my finger

[AntonyH]

Thanks, that's good news. Guess I'll have it fitted first and see what happens...

As mentioned the current filler either causes pumps to click off every half litre, or not at all, seemingly dependent on pump nozzle design and tiny differences to how I hold and angle the nozzle, so at the very worst, it's going to be no worse than now!