I'm thinking of doing a top end rebuild due to a tapping sound from the left bank rear. I was hoping to do this without pulling the lump. Has anyone done a top end rebuild in situe, if so what are the pitfalls.

if you mean replacing the lifters, then yes..it can be done with the engine in the car.

but needs removal of a lot of things (plenum, rocker covers, cambelt, camshafts)

i have done the valve stem seals in situe bit of a pita but yep it can be done matey

the only PITA is removing the egr from the plenum,thats about the only fiddly part,rest is straight forward if you have stripped the front of the engine before and you have a manual

 

top tip if your replacing the lifters use a magnetic pickup tool to pull each lifter,that way you dont drip oil every where and you can drop all the old lifters straight in to a container,new lifters come in a sealed packet containing oil,keep lifter upright on removal then get them in