Renwick and Bertelli had been in partnership some years and had developed an overhead-cam four-cylinder engine using Renwick's patented combustion chamber design, which they had tested in an Enfield-Allday chassis.
Renwick & Bertelli foran en colaboradores algúns anos e desenvolveran un motor de catro cilindros e árbore de levas usando deseño da cámara de combustión patentada de Renwick, que probaran nun chasis de Enfield Allday.