Is there some problem with declaring a pan?
Obviously a heartbeat-raising moment for you, but if you want priority to get the thing on the ground, that'd be the way to go.
If you didn't declare an emergency, or only 'sort of' did by saying something like "I've got a bit of an engine issue that I'm working on here," you may be doing yourself a disservice. In my experience ATC almost always do a good job of helping us out in emergencies anyway, but why not make it clear-cut and say the magic words that put you unambiguously at the head of the queue?
There was another thread a little while back about a certain Australian airline flight diverting with smoke and fumes which I heard on the airways as it was happening - their words to ATC were to the effect that they were 'ops normal', but with the above-mentioned issues going on. If that's ops normal for those guys, remind me not to book any more flights with them!
I understand there may be company sensitivity about drawing media attention, but if that stops people declaring emergencies then the tail's wagging the dog way too much.