I cranked the engine while the wire connecting the coil to the distributor was removed in order to not spark the engine.
Apparently this is not the right way to do it. Have I caused some damage by doing this?
I would disconnect the supply to the coil, but it does depend on which coil / ignition system is fitted.
If it is the older type non electronic then it will be fine.
However any of the electronic types can suffer damage sometimes but not always.
After building an engine I would spin it without plugs and the coil disconnected to get the oil circulated and the pressure up then fit plugs and fire up.