How do you know when you're driving your oval hard? When you can smell fuel.
I've always been a worried by the fact that my fuel tank leaks at the cap when I'm circuit racing. I've tried to solve it by fiddling with the original cap.
The closest I got was using a more sturdy accessory cap with a new gasket. But the trouble is that the oval tank has no venting system and has to vent through the cap. Unfortunately this not only allows air in but fuel out.
After coming off the track it was routine to open the bonnet and mop up the fuel. This happend so regularly I have fuel stains on the powder coated tank.
I've finally done something about it. On the weekend I put a pipe in the filler neck as a vent and added a neat motorcycle style filler where the cap used to go. Not bad for a back yard effort ah?
Together with the big fuel fitting on the bottom of the tank and the 3M aircraft fuel resistant coating on the inside I'm pretty happy with my fuel tank. I've just got to reduce the fuel sloshing around. Perhaps some foam blocks from revolution race gear in the future
I had issues with fuel delivery too. I installed an alloy fuel injection surge tank in the front of the car. This is fed with a facet style fuel pump. This pump is susposed to deliver 3psi of fuel, but tests on two of them only supplied .5psi at the best.
This fills the surge tank, overfill is then fed back in to the main tank.
A holley blue then pushes the fuel from the surge tank through to the regulator, then the carbs.
The standard fuel system wasn't flowing enough and the engine was overheating.
Hey CT looking good, you really should do a write up about your car with lots of pictures for the world to appreciate. Either that or I'll have to come to Sydney to take my own 🙂
I put a lot of thought into solving the problem. However the key was finding a fuel filler fitting that fitted the oval tank. That filler is really high quality but also expensive. I really ummed and ahhhed about forking out the money for it. In the end it's perfect fit and the safety aspect had me opening my wallet.
All you really have to do is create a flat surface for the fuel filler. That means reshaping the lip that ther regular cap rotates and locks into. Then drill the 6 holes for the filler. The filler bolts to a C shaped bracket that is on the underside of the fuel tank lip. Tightening the screws sandwiches the tank lip and a cork gasket between the bracket and filler mechanism.
The vent was made with copper pipe and braised into the neck using an oxy welder(plumber style).
The hardest part is neutralising the fuel vapour. EVEN IF A FUEL TANK HAS BEEN EMPTY FOR YEARS IT MAY STILL EXPLODE WITH A SPARK.
I rinsed the fuel tank with degreaser and water. Then I ran my car exhaust through the tank the for a few minutes. Exhaust fumes neutralise the the petrol. Then, just to be safe, I filled the tank with water all the way up to the filler neck while I worked on it.
I priced a custom aluminium tank a while ago and it would've cost over $1000. Modifying the standard tank was a third the cost.
Did you look/think about using the later model screw type filler cap and fitting/welding this onto your existing tank ? not to sure on the size compatability.
