converting petrol to diesel and vice versa is a PITA because you need to change the fuel tank, sometimes the fuel lines, dash and engine bay looms (to make the instruments work), gearbox/clutch, engine mounts are different also. and the diesel engine is so heavy, you'd need springs off an escort diesel to take the weight

better off starting with a 1.8D escort van, and putting the mondeo 1.8TD into it.