Back story: I have had an exchange case come in for the 2.5 treatment, but unfortnately the bellhousing guide stud tappings had been terminally spoiled by unskilled hands (timeserts installed so far out of position / out of square that the studs had been bent to try and make the transmission fit...)
I couldn't even get a spare bellhousing to look at the engine.
The only option was to recover all the good head studs and transfer them to a good donor case that needed five or six replacing.
Here are my choice of tools:
200 quids worth of eyeglass -inspected studs saved, for the sake of an hours work:
These five condemned, all the corrosion patches are lined up. This is after a good scrub with scotchbrite:
Anything other than a slight stain should be inspected closely. It will only bite you on the backside later.
Anyway, all out and no breakages, some tighter than others, but all removed without incident.
I would never attempt this work on a stone cold crankcase or on one that has still got the crank and rods in, but if you were in a desperate spot then heat is your friend and plenty of it! A Ronson disposable cartridge gas torch is not going to put enough heat into the case quickly enough, being as its basically a big heat-sink.
Heat is closely followed by a self-tightening chuck extractor and a good bit of leverage to get the studs moving. They all creak as they release, the impact driver just makes the job faster in the workshop.
