Austin Seven single-seater

The British Motor Museum, adjacent to the Jaguar Land-Rover HQ at Gaydon, is home to not only vehicles of all shapes and sizes from this country’s motoring heritage, but also many interactive exhibits as well as printed and visual content – it’s a great visit for all ages.  KW Heritage were approached to find a solution to a poorly performing SU Carburettor used on a 1936 Austin Seven single-seat racing car.  The car’s 4 cylinder, 747cc supercharged engine produced 116 bhp at 8590 rpm, but was designed to be revved to 12,000 rpm!

The challenge

  • Discuss and understand the method of operation of the Carburettor and it’s particular fault which meant that the engine wouldn’t idle, likely due to local heat induced distortion of the Housing as a result of repair welding a mounting lug.
  • Working to a budget, propose a cost effective solution.
  • For reasons of authenticity, retain as many of the original components of the Carburettor as practicable.

The approach

  • Conclude with the customer that a rework of the Housing and Piston would provide an effective solution.
  • By selecting a trusted supplier, KW Heritage were able to communicate requirements verbally and via email. This pragmatic approach negated the need for any remanufacturing and the associated engineering time.

The results

  • Housing – by removing minimal material from the bore of the Housing, it was returned to a smooth, round profile, free from distortion.
  • Piston – material was removed from the grooved working shoulder and a replacement sleeve turned up and fitted in place.
  • The reworked assembly was returned to the customer for fine tuning prior to being reunited with the engine, where it’s correct function was re-established.


It has been a pleasure working with Ed and the team at KW Heritage. We initially discussed a proposed solution to our problem, and as with all processes involving historic vehicles a few changes to the plan were needed along the way. These were communicated promptly by Ed and jointly we agreed on the necessary additional work. We are very happy with the end result, with the carburettor working as good as new. Paul Gilder, British Motor Museum.


Further details about this car can be found here:

1936 Austin Seven twin cam single seater_BMM

For more information on KW’s range of Heritage Engineering services, visit the KWH website.