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overfilling kit cars with fuel

number-1 - 11/6/18 at 09:54 AM

I was behind a few kit cars yesterday and noticed that quiet a few had petrol marks under the filler cap. Some were pretty bad. Is this a common thing on kit cars?

I presume the auto shut off on the petrol station pump didnt shut off and its overfilled?

Is there a soloution.....apart from fill up and listen carfeully

adithorp - 11/6/18 at 10:03 AM

If they were 7s with filler on the back panel... It's common that they're difficult to fill, often getting airlocked and splashing back. That leaves stains down the panel.

Also with short necks fuel surge can easily get to cap height so if it's nothing a great seal it'll leak.

leon51274 - 11/6/18 at 10:10 AM

Yes they are a right royal pain in the arse to fill without it splashing out the back.

It takes a bit of a knack and I just make sure I trickle the fuel in without brimming the tank.

Irony - 11/6/18 at 04:18 PM

When overfilled mine chucks fuel out the air breather. The breather tube wraps around the tank to prevent fuel spilling out in a roll over. However when the tank is full to brim the system doesn't work. Ideally I shouldn't crash with a full tank. Which is easy with a V8.

number-1 - 11/6/18 at 08:33 PM

Hahaha V8s are uncrashable..... and yep, they were tiger avon/7 style cars

Isnt there something that can be done to stop this? Why does it stop on a normal car but not a kit car? Maybe google will help me answer this but id rather hear the locost reason

jacko - 11/6/18 at 08:36 PM

35l fuel tank over diff
this is how i stopped mine doing what your asking about

snapper - 11/6/18 at 08:50 PM

quote:
Originally posted by Irony
When overfilled mine chucks fuel out the air breather. The breather tube wraps around the tank to prevent fuel spilling out in a roll over. However when the tank is full to brim the system doesn't work. Ideally I shouldn't crash with a full tank. Which is easy with a V8.

I’d fix that properly ASAP

You can set breathers up with roll over valves and one way valves, I have 2 breathers, one is a pressure out with a roll over valve and the other is an air in with a one way valve for when the tank empties.

I still need to be very soft when filling as it will spit back

AntonUK - 11/6/18 at 10:03 PM

Out of interest, how much 'air space' should there be at the top of a typical 7 style tank. I typically try and leave an inch or two.

Irony - 12/6/18 at 03:34 PM

quote:
Originally posted by snapper

quote:
Originally posted by Irony
When overfilled mine chucks fuel out the air breather. The breather tube wraps around the tank to prevent fuel spilling out in a roll over. However when the tank is full to brim the system doesn't work. Ideally I shouldn't crash with a full tank. Which is easy with a V8.

I’d fix that properly ASAP

You can set breathers up with roll over valves and one way valves, I have 2 breathers, one is a pressure out with a roll over valve and the other is an air in with a one way valve for when the tank empties.

I still need to be very soft when filling as it will spit back

I probably should sort it but the roll over valves are expensive and there is a great post on here about the wrap around method. Essentially the breather tube wraps around the tank so a part of the tube is always above the level of the tank. So in a roll over and the car is upside down the breather pipe in mine will be sticking straight up above the level of the tank. The system only purges fuel out when I overfill

jossey - 12/6/18 at 07:27 PM

A lot of cheap filler caps leak too. I've been on many trackdays where fuel is pissing out of the filler top when they accelerate. Mine included. I solved mine by reducing how much I fill it and moved the filler to the top rear boot lid. Also replaced the Chinese filler with a decent one.