Good morning

I just put brand new engine in my k74 and its making a knocking noise I tryed so many different things new belt gear timing and so on and I can't work out what it is. Taken to garage and they saying they ain't sure and will have to take head ect off for £80 hr. Is there anyone close to Coventry that know the trucks well that will come and take a look and help me sort it out I will be paying just really need this sorting now. Many thanks dave