Fuel things

Today I was going to look at the charging system but changed my mind and instead focused on the fuel side of life. The petrol tank was custom made when the body was crafted and it mimics the original tank in looks but aside from that it is unique being made from aluminum with a few customisations. The fuel sender is a marine item whereby the fuel level in the tank is measured by a bobbin that floats up a vertical sensor shaft. Realistically, there are no moving parts to the sender as the bobbin is not actually attached to anything – the shaft senses where the bobbin is and sends a specific resistance down the sensor wire to the gauge within the range 0-180 ohms (0 being empty). Trouble is vintage fuel gauges had totally different resistance ranges and in all the spares I had the range was 250-0 ohms. Completely opposite in functionality. For a while therefore I am forced to use a modern alternative which sort of looks alright but sadly not really what i want… hey-ho I need to know the fuel level so this is put back on the job list for another day. On the positive side I know that this part of the new wiring does actually work.

My other non period customisation is to insert an inline fuel filter as a just-in-case. The tank may have tiny pieces of aluminium dust still inside which would not be great inside the combustion  chamber and it also gives me a visual that fuel is actively being pulled from the tank to the engine.

Below is the engine bay with the newly provided fuel system. It finally looks like a proper vintage racing engine. One day I will get round to polishing both the rocker covers on the top of the engine.

I may remake the copper pipe that runs from the petrol pump (top left) down to the first carburetor – I think I can improve on the route and I sense the 360 loop is not actually necessary. Sadly whilst I am making huge strides forwards I do have a few issues to resolve:

  • Cylinder 3 is noticeably running hotter than the other cylinders (really weird)
  • The rear carburetor has a slight fuel leak (which may account for the above issue)
  • There doesn’t appear to be any oil getting to the inlet valve rocker shaft

I also took a look at the fuel/air mixture and I found the front carburetor was set too rich so I spent a happy hour ensuring the fuel levels were the same in both carburetors. That will make a difference to the tuning and it also meant I had to remake the mechanical choke connections because the length of the original ones were too short resulting in their enriching the front carburetor without my knowing. This is all resolved now.

All of the technical issues need to be addressed before the car can be driven – oh…. and I need to rebuild the entire braking system which had slipped my mind for a while 🙂

We are getting ever closer to driving the car after which I fully expect to unearth a whole host of other challenges….


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