The carburettor heatshield sits between the exhaust manifold and the SU carburettors, protecting the fuel and float chambers from radiated exhaust heat. A polished stainless steel heatshield performs this function more effectively and durably than the original item, while adding a smart, period-correct finish to the engine bay. It is a popular upgrade combining a practical benefit with improved appearance.
Why Heat Management Matters
The SU carburettors fitted to the A-Series Midget sit close to the exhaust manifold, and excessive transferred heat raises the temperature of the fuel in the float chambers. This causes fuel vaporisation, leading to difficult hot starting, rough running when warm, and hesitation in traffic, problems that worsen with modern fuels, which are more volatile than the petrol of the era. An effective heatshield is the first line of defence against these symptoms.
Stainless Steel Construction
A polished stainless steel heatshield resists the corrosion and discolouration that affects the original plated steel item over time, and reflects radiant heat effectively. The polished finish is both functional and attractive, lifting the appearance of the engine bay. The shield mounts on the carburettor studs between the inlet and the heat source, retaining the original layout.
Application and Fitment
The heatshield is specific to the carburettor installation fitted to the car, so the carburettor type and arrangement should be confirmed before ordering. It is fitted with the appropriate spacers and gaskets that also serve to insulate the carburettor from conducted heat through the inlet manifold. Renewing the insulating spacers and gaskets alongside the shield gives the best result.
Ordering Considerations
Confirm the carburettor specification of the car before ordering, as the heatshield and its mounting differ with the carburettor installation. A polished heatshield is most beneficial on cars suffering hot-start or warm-running problems, and is commonly fitted alongside insulating spacers for the most complete reduction in transferred heat.