[v8volvo]

The TDI guys when putting head studs in do sometimes use the method of doing them one at a time with the head in place. Have to be very careful and deliberate with the torquing process, but if you look around there you'll probably find some how-tos and success stories.

I think the logic is that getting the block threads squeaky clean and friction-free is less important when using studs, since the studs get screwed into the block under no tension (unlike the stock head bolts), reducing the friction that would otherwise be there fighting the bolt as it screws in. And anyway, unlike with the stock bolts, any rotational friction in the block threads that did exist wouldn't have an effect on ultimate installation torque and clamping force of the stud, since that is controlled instead on the other end where the new clean nut is screwing onto new clean (and lubed) stud threads. So for those reasons those TDI folks seem to have decent results with this method when they do it carefully.

Also remember, though, that those TDI engines, unlike a D24T, have a metal head gasket from the factory plus direct injection that puts less thermal stress on the cylinder head and headgasket, so by their design they are less susceptible to head gasket leaks and more forgiving of mistakes. Plus the engines are 10-20 years newer and thus the effects of aging are less pronounced. On a D24T in a Volvo, taking the opportunity to renew the headgasket while putting head studs in by doing it with head off is probably the better way to go, especially if the rationale of the studs is that you are planning to push the limits of the engine. Running on the edge with a 30-year-old composition headgasket is asking for trouble, no matter what kind of hardware you are holding the head down with.

As far as "prep" the biggest question is this:

Do you have, or have access to, the complete set of factory tools that is required to remove and reinstall the timing belts and related components as part of a cylinder head R&R?