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How to start a Hot-Bulb Engine - Vierzon 201

We are so excited to share this latest arrival with you – what a uniquely charming tractor this is!

Whilst very little is known about the most recent ownership of this tractor, the history of this French company is quite a story.

The Vierzon 201 is a single cylinder diesel tractor which was manufactured in France by a company called Société Française de Vierzon (SFV). The 201 was produced between 1953 -1957 and is described as a semi-diesel, hot-bulb single cylinder tractor.

The hot-bulb engine is a type of internal combustion engine. A blowtorch can be used to heat the bulb, fuel then ignites when it comes into contact with the red-hot metal surface inside the bulb, followed by the introduction of air compressed into the hot-bulb chamber by the rising pistons. The whole process is actually quite straightforward - we have produced a short video which demonstrates how this tractor is started. (Shown below).

The Vierzon 201 is extremely lightweight, weighing just 1200kg - this highly unusual tractor would make an ideal candidate to take to shows and rallies.

SFV was founded by Célestin Gérard who initially trained as a carpenter, but throughout his life became recognised as an inventor and industrial pioneer.

Gérards early career saw him repairing farm equipment alongside his skilled work as a carpenter. Gérards talents and ingenuity were recognised when he undertook the task of building a threshing machine for his father and in 1848 he established a workshop in Vierzon.

Over the years he produced a range of award-winning agricultural implements including winnowing machines, root-slicers and of course, a range of threshing machines.

The enterprise continued to grow and in 1878 it became known as The Société Française de Vierzon. The company commenced production of steam powered machinery in 1861 but it was 1931 before they produced their first tractor.

The majority of SF Vierzon tractors were of the horizontal two-stroke semi-diesel type. During the 1930's and up to the mid 1950's these tractors provided the motive power for driving belt powered machinery such as threshing machines.

While they could hold their own when pulling trailed implements, by the mid 1950's the products of other competitors were much more user friendly and despite an attempt to catch up with a new range of Peugeot diesel powered tractors, it was too little, too late and the Société ceased trading in the early 1960's.

A quick Google search often returns a mountain of information when researching these older tractors but very little data was available for this unique Vierzon and of course, the majority of the information was in French so my understanding was limited to say the least! So credit must be given to Tractor Data for the majority of this information, alongside Wikipedia and the fountain of knowledge that is Matt, for explaining to me how a hot-bulb engine works!

We hope you enjoy reading these short blogs as much as we enjoy putting them together. We'd love to hear your comments. What would you like to see next?

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