This section covers the fuel storage, delivery, and distribution components from the fuel tank through the fuel pump to the carburettor feed, the complete fuel delivery chain. The fuel tank, fuel pump, and fuel line routing all differ between the TD and TF, and within the TF's own production run the fuel pump specification changes at a critical chassis number breakpoint.
Fuel Tanks
The fuel tank is a 12½-gallon capacity unit mounted at the rear of the chassis, strapped over rubber packing. The TD and TF use different tanks, the TD tank has its own support brackets that mount to the body, whilst the TF tank uses different support brackets together with separate upper and lower strap brackets. Both tanks feature chrome-plated end panels available in sets, a fuel drain plug with fibre washer, and a fuel pipe adaptor with integral solder-in filter at the tank outlet. The fuel filler cap is shared between the TD and TF in the original pattern, with an alternative TC-style cap available.
The release clip and filler seal are common to both. The rubber pad sets that cushion the tank against the chassis, the rubber packing strips under the straps, and the strap fixing hardware are model-specific between TD and TF. Tank straps are available in either primed or chrome finish.
Fuel Pumps
The SU electric fuel pump is available in both the original points type and an improved electronic type for each specification. The electronic pump replaces the conventional contact-breaker points with solid-state electronics, eliminating the most common cause of pump failure, worn or burned points that fail to make contact. For the later TF pump, electronic versions are available in a positive-earth-only specification for cars retaining the original wiring polarity, and in a dual-polarity specification that also suits cars converted to negative earth.
The standard TD and the early TF up to chassis 1509 use a low-pressure type pump, supplied singly for the standard TD, or in pairs for the TD Mark II dual-pump installation. From TF chassis 1510, a high-pressure type pump was fitted. The pump mounting kit, including rubber pads and retaining plates, is specific to the installation: the TD and early TF kit mounts the pump on the bulkhead, whilst the later TF kit mounts the pump on the right-hand chassis side member with a rubber cover protecting it from road spray.
Fuel Lines and Hoses
The fuel pipe from tank to pump, the flexible hose from pump to the rear carburettor, the inter-carburettor connection, and the banjo unions and fibre washers at each connection point all vary between the TD/early TF, the late TF, and the TD Mark II specifications. The TD Mark II has its own unique fuel line layout accommodating the dual-pump installation, with additional pipes, hoses, and an adaptor connecting the secondary pump to the front carburettor. Fuel and brake pipe straps, together with the chassis clips that secure the pipes to the chassis rails, are supplied in the correct quantities for each specification, the clip count varies between models and between left-hand and right-hand drive cars.
Fuel Sender Unit and Fuel Level Indication
The fuel tank sender unit and its gasket are common across the TD and TF, secured to the tank by six screws. Neither the TD nor the TF was fitted with a continuous fuel level gauge on the dashboard. On the TD, fuel level is indicated by a green warning light that illuminates when the level drops below a threshold. The TF uses a similar arrangement with a blue low-fuel warning lamp; the TF's three-in-one instrument panel carries the ammeter, oil pressure gauge, and water temperature gauge, not a fuel gauge.
When ordering a replacement sender, it is important to confirm the dashboard arrangement so that the sender and indicator specification are matched.
Fuel Filtration and Additives
Chrome fuel filters with toughened glass bowls are available in two union sizes, 1/4-inch for the standard TD pipe diameter, and 5/16-inch for cars with the larger-bore fuel lines. Adding an inline fuel filter is a sensible modification for any TD or TF that does not already have one, as dirt and debris in the fuel can cause the carburettor float chamber needle valves to stick open, resulting in flooding. Castrol Valvemaster Plus is available as an octane booster for owners running on modern unleaded fuel, it reduces pinking and knocking, and may avoid the need to retune the engine when the original leaded-fuel compression ratio is retained. One 250ml bottle treats 250 litres of fuel.