BRILLIANT BDA

Following the Lotus Twin Cam (no relation), the ‘Belt Drive A-type’ (above) was another clever twin-cam permutation on Ford’s tough ‘Kent’ bottom end, this time with four valves per cylinder, devised by Mike Hall. Both these engines are technically three-cam, because the original camshaft is left in place low down on the right of the block to drive the distributor and oil pump. Homologated at 1601cc and first fitted in the Escort to create the RS1600 of 1970, it was also seen in later BDG 1975cc alloy-block form in Mk2 Escorts, Caterhams (as the BDR) and as the short-stroke 1300 BDH. The 1599cc BDD and BDM versions were the mainstay of Formula Atlantic in the ’70s. The turbocharged BDT powered the RS1700T then the Ford RS200, at 1803cc.