Try these guys out as wellhttp://www.isuzuperformance.com/isupage/
What car is the engine in?
Does the smoke smell of oil or diesel? If oil look at the turbo If diesel there must be a problem with the pump injectors or timing. If you had the cam belt off did it go on correctly timed.
Running hot could be timing or a bad turbo but could also be a blocked or worn out radiator. Also if the car did not have this engine originally the radiator might be too small or the pipes might be kinked