i now this pops out easily but I can't figure out how to get it out? I see a small port on the underside that has a bit of brass or something in there. What do you do to get it out?

I'm converting a Sierra to Scorpio tibbe keys.

 

Don´t remember exactly but I think there's a little piston in the cylindrical piece that locks that piece into the hole.Turn the key on various positions an try to put the piston down, then if it works pull out the cylinder

Sorry, I don't know how to explian it better

 

I must not be looking hard enough as I've searched and some say there is a thing on top (a piston as you say) but I don't see much.

I'll go back out to the garage and give it a shot. It's -7 outside and I'm not too excited about messing about out there!

 

There is a spring steel clip on the bottom of the ignition. You press it in with a pick or flathead and when the ignition is dead center of position I you pull it out.

It has to be RIGHT at position I.