Dorman Diesels Ltd were engine manufacturers of Stafford, England. The company wasa subsidiary of Perkins Diesels of Peterborough. Perkins are a subsidiary of Caterpillar following their purchase of the company from Massey-Ferguson on the break up of the Varity group. In September 2010 Perkins Engines agreed to sell all Dorman Diesels non-SE related parts to Lincoln Diesels Limited including the ST, DA,Q, J, L, LS, P, Y, Monair, F, DWD engine ranges.