I'm currently in the process of retiming my 95 monte Z34, which jumped time... Currently, we've gotten everything locked down, and the cam sprocket bolts are all broken loose, but we have an issue... The sprockets are seized to the camshafts, meaning they're not able to freely spin. For this engine to be timed properly these need to be able to spin freely. Does anyone have any advice on how to get them loose, other than to wack them with a hammer? I don't wanna risk damaging these sprockets since:
A. They're hard to find...
B. They're very expensive...
C. I don't wanna dump and more money into this car until it proves that it CAN be reliable.

So... With that in mind, are there any known methods to free up the cam sprockets on this 3.4L DOHC without damaging them?