i think i'm about to upset the apple cart here!!! i have recntly change the belts etc on my JTS 2.0L differnt camlocks required but basically the same. i wrangled with this before i changed my variator. However, i removed the variator with the cam in place. i did not fit longer bolts to hold the cam locks either. You try ordering some bolts in M7 thread!!! I found that the variator was not tight enough to even begin to pull the thread out of the head.
i am an experienced engineer and as such i will qualify this by saying the following.
The risk is yours to take, i may have been lucky who knows. i felt the tension of the variator and would not have pulled excessivly on it, if it had felt really tight i would have stopped and taken the camshaft out, as it was it was it came loose with relatively little effort. generally if the experts /dealers recomend you remove it i would listen to them as it won't take much more time. the cost in your time is well worth it as it removes all doubt and all risk. I just wanted you to know that it is possible but its your risk.
A bit of friendly advice.
If you do remove the camshaft, before you do please ensure you mark each camshaft cap. Not only in which order they are 1, 2, 3 etc but also which direction they faced by marking an arrow pointing towards the front of each one before you remove them. keep them very clean and bear in mind the shiney bit around the inside of the cap is very very soft so take great care not to scratch it, put them in a clean tuppa wear box with a lid or something like that, when re-fitting gently apply some clean engine oil to them with the tip if your clean little finger but don't scratch them with your nail. Hope this helps! Good luck.
ALFA 156 2.0L JTS SPORTWAGON