Timing pinion woodruff key

Penetratingting oil left to stand a few days - light tapping now and then to set up a lititle vibration - drive out by aligning drift                     ( screwdriver ?) axialy and upwards to rock key out of slot .

If you've got a really decent pair of 'Vise-Grip' wrenches with new square jaws and undamaged faces, and the key has square flanks, they can sometimes be gripped on really hard and used to 'wiggle' a bit and worry the thing a little loose. You won't pull it out with them, but sometimes enough to get it moving.

Unfortunately, until the key is removed, the crank won't pass through the oil disc.

If you're lucky you can get a thin screwdriver under the jaws when you've grabbed the key and lever it off. If the jaws are worn / rounded it would be worth while facing them off on the grinder.

Another way is a thin screwdriver (jewellers' type or ground down electricians' type) used as a wedge underneath one end of the key and tapped lightly with a pin hammer although that will probably destroy the screwdriver.