Anybody seen this before?

[Guest]

Hello all, this is my first post on blatchat TechTalk, my car is a Supersport which I built last year and finally got registered in January this year. I've not had too bad an experience up until now. I have a problem with the fuel cap and possibly the fuel tank breather which has had a knock on effect of wrecking the paint work below the fuel cap. The problem became apparent on Sunday at the North Herts meet when I parked the car on a slope with the drivers side facing downhill slightly. The fuel tank was approximately 3/4 full. We noticed the smell of petrol but I thought it was one of the other older carburetor cars until I looked at the back of my car to see petrol weeping out from behind the filler cap and a large blister in the paint work where it has completely lifted off the aluminium skin. http://www.cowler.com/Seven/paintReaction.JPG ☹️

 

Has anyone had a similar experience?

 

I'm in communication with Caterham to get the problem sorted and as you can imagine not to happy at the moment.

[Myles]

While you're getting this sorted, it is probably worth checking/fitting a non-return valve in the breather to stop fuel sloshing out on left-hand corners. Plenty in the archives from years-past if you search.

 

Moderately surprised to hear about the paint lifting by the way - the old traditional side-effect of spilt fuel in the 7 is the fog light and/or connections cracking up...

[tiddy1]

There is something seriously wrong with your paint, you should be able to slosh petrol over it without any adverse effects.

 

As to the leakage, you should not be able to get the fuel level that high unless you were parked on a serious slope. however there are several areas to check on the filler cap

 

1. the cap fitting into the funnel, this should have a god o-ring to give a seal

2. the gasket between the outer aluminium part and the inner funnel

3. the big rubber pipe connection to the filler and tank (jublie clips)

4. the breathers on the side of the filler (small pipes)

 

start with those and see if there are any leaks

 

Simon

[Rattie]

I suspect we'll be seeing more of this with some water based paints. It looks like the patch I had lift from brake fluid. At least I knew that was a risk, petrol, not so much.

 

The one way valves allow pressure to build up in the tank, so you do need to adjust the o-ring compression on the filler cap to keep it in, like Simon says in his no.1 suggestion.

 

I had quite a bit of slosh out under trackday accelerations before tightening up the filler cap. It's a nyloc nut on the inside of the filler, working against a spring.

[Guest]

Thanks for all your replies, so far a lot more than I've had from CC. Just had a look at the cap and tightened the nut above the spring and when I fit the cap back in and press the leaver down it feels a much tighter fit. I have a feeling that might stop the leaking. I'll put one side of the car on a ramp tomorrow to see if that stops it. Then on to CC to see what they can do about the paint.

 

[Hodsonpe]

Hmm, my Yamaha tank did this too. Modern paint is 🙆🏻

 

Paul.

[Guest]

Booked the car into CC Dartford to look at the paint and check the fuel filler, will post the outcome. Hopefully it will be a happy one.

[Jason Plato]

if this is what happens to the latest caterham paint I can see this issue being a big one for all the new owners....

with the flap in place it's virtually impossible not to have paint getting splashed in fuel

[eagle]

It's almost like the fuel's gone under the paint though and lifted it off the bodywork, otherwise I'd expect it to have stripped it from the outside in. Very strange indeed.