Fuel overflow management

I have been hauled up on several occasions about fuel discharge during track days and sprint/hill climb events. This only happens when the tank is above half full. I fitted a Mocal valve which I thought would cure the problem as it has a dual function a) When the vacuum in the tank exceeds 0.5bar it will ingest air from outside. b) If however the tank pressure increases due to temperature effects (or sloshing) then the valve release in the other direction if that pressure exceeds 0.75bar. By this method the valve can act as a roll over valve and hopefully keep the fuel in the tank.

The problem occurs on track days when the fuel is warming up (so positive pressure) and the corners pull some g, if now the pressure release happens on a right hander then fuel is emitted momentarily till threshold of the valve closing is reached.

I have tried fitting a catch tank (jam jar) but this only delays the problem till the catch tank is overflowed. This results in dumping fuel from the catch tank between sessions.

The answer may be quite simple, let the main tank overflow when positive pressure exists, collect the fuel and suck it back in when the fuel is used up and the pressure becomes negative.

principle

catch tank mounted under chassis

I will let you know if it works.

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New brakes and oil pres warning lamp

  The brakes have been a problem from day one in that they were causing lost time at the hairpin and fading two up. They looked the part being single x drilled discs and early billeted 4 pot Dynalite's  from Wilwood.

I changed the discs to vented x drilled and grooved parts and as a consequence had to upgrade the callipers as well to the latest Dynalite forged part from Wilwood supplied by RD.

Dynalites with vented discs

The results were a dramatic improvement in both hill climbs and circuits.

Oil pressure warning

I have been advised by several hill climb veterans that a very bright visible oil pressure lost lamp is essential equipment for racing. This lamp BL0102-14-34 is the bees knees. Thanks to Matt as he had a spare in his garage.

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