Cam Angle Targets

“In most instances, if we're considering a variable intake camshaft, the mechanical installation is designed so that when the actuator isn't being energised, the cam will sit in its most retarded position.“ and What does "the most retarded position" mean?

The cam can be advanced from it's most retarded position. Normally this is the position the cam will assume if the ECU connection to the controlling mechanism (often an oil control solenoid) is disconnected. Typically this will be the "0 deg of cam advance position".

You do have to be careful, though, as some applications have the default as the advanced position, with any adjustments retarding from there.

In addition to what was already mentioned, I've seen intake cam phasing applications which have advance from 0 only, others advance or retard from centerline, exhaust is sometimes retard only, other applications allow exhaust cam advance or retard from centerline. There may be others I've not run into which only retard the intake cam, or only advance the exhaust cam, so there's quite a range of behavior.

With the solenoid unplugged many systems don't sit on centerline, and have to be driven there, though many will sit within a few degrees of centerline while unplugged. This is not consistent so testing to confirm is always suggested.