thanks for the advise ianifm, so i have to remove the flywheel, gearbox and oil pump? also to replace conrod i will have to remove the head, sounds a bit daunting
Yep. To be honest, it'll be a lot easier with the engine out of the car. For that you'll need to buy or rent a crane, really.
Either way, your (generalised) plan of attack will be:
Separate gearbox from engine
Lock crankshaft (I've used a bit of softish wood before, but a proper lock isn't much - try Aftermarket Tools for your Alfa Romeo TwinSpark, JTS, JTD, V6 and Twin Cam Engines :: TotallyAlfa
Remove cambelt pulleys and oil pump
Remove clutch and flywheel
Remove rear oil seal
Remove big-end and main bearing caps to release crankshaft
Take head off
Remove piston with dead conrod
Ping out a circlip from the piston to remove the gudgeon pin. Try to listen for where it lands
...then put it all back together again.
There's a good head-removal guide here: http://www.alfaowner.com/Forum/alfa-...t-failure.html
The engines are really quite simple to work on. I learnt how to do this by basically doing what you've got in store.
Edit: Make sure you inspect everything for scores/wear etc. You also need to get rid of all traces of that ground-up shell from the engine as well (it's very abrasive). Take the baffle plate out of the sump, and remove the panel from underneath and clean that until it's spotless, as well as the oil pick-up pipe and oil pump. I've also seen it get into the variable-inlet manifold somehow!