EVOLUTION OF THE MIGHTY YB

The YB engine series has its roots in the venerable Ford Pinto block – a cast-iron, sohc 1993cc ‘four’ introduced in 1970, built in Cologne and first seen in Britain in the Mk3 Cortina. It was also used in the Pinto subcompact in the US, hence its nickname (Ford’s internal designation is T88). Cosworth developed a twin-cam version, the YAA, which was adopted by Ford in its turbocharged form, the YB, with a thicker block and steel rather than cast-iron crank and rods.

Cosworth’s twin-cam, 16-valve head used hydraulic tappets, initially making 204bhp in road and 370bhp in race trims, but the RS500 allowed around 500bhp in BTCC/DTM Group A racers, with claims of more than 600bhp from Australian teams come the end of the Group A era in ’92. You identify them by the cam-cover colour: red for the YBB (Sierra Cosworth 2WD), YBD (Sierra RS500) and YBJ (Sapphire 4WD, non-cat); green for the catalystequipped YBG (4WD Sapphire); blue for the YBT (large-turbo Escort Cosworth); and silver for the YBP (small-turbo Escort).