right i have the ford focus 199 t reg 1.8 diesel gear and need some advice on the engine please, when i try to start the car it tries to fire but wont start but after turning over for a fair while it does start but it produces a loud knocking noise and black smoke out the exhaust been told first off was pump then the cam follower and now the pistons dropped, could anybody give me any advice on this and if the engine is knackered would any other ford engine fit my car, thanks in advance