Actually I searched in every site and forum I know about spanish (and not only spanish) cars, without any result...than I try with a normal Google research with the only clues I had, "automovil seis cilindros 1924-1925-1926-1927-1928 espana", and I found the site where it's pictured. It seems that Mr.Gradè studied and perhaps realized an engine with a very strange cylinders-disposition, and a particular carburator too. Thank you for the Lock, without it I would have probably overcame by quicker quizzer or I would have quit my research before finding it.