The FOK range of model diesels was manufactured in Hungary between 1963 and 1969. The range replaced the earlier Alag, Proton and VT marques which had all ceased production as of 1961. Many of the FOK engines were marketed in Germany as the Engel Rebell series, while others were sold in Britain by Ripmax under their own name.
The FOK engines were manufactured in three displacements - 1 cc, 1.5 cc and 2.5 cc. They were identified by their metric displacements rather than the cubic inch equivalents - for example, the 1.5 cc model was designated as the FOK 15. This may cause some confusion among collectors accustomed to the cubic inch displacement standard.
Apart from their relative dimensions, the three models were readily distinguished by their colour-anodized components - gold, blue and green respectively. All were built to a common basic design, which was significantly amended part-way through the production run. The quality of their construction was high, while their performance was well up to prevailng standards for plain-bearing sports diesels. All told, some 60,000 examples of all types were manufactured during their six-year production period.
The FOK engines were covered briefly in the previously-cited article on this site about the VT engines. Full details of the FOK range may be found elsewhere on this site in a separate article.