I had this happen too (but on my k5). In my case, the woodruff key kept messing up. Once it had spun it messed up the end of the crank, but looked ok to me. I ran a flywheel weight for a time to ensure that it would stay together. flywheel weights have a center mount plus have set screws around the perimeter. I ditched the flywheel weight once I had a different crank in it. Spark is sometimes hard to see during the day, but pretty easy when its dark. Also I noticed, if I pulled the plug, put it in the boot and really kicked it, it was even easier to see the spark than when slowly rolling the engine over. Also when my key spun, I had pieces that were stuck to the magnets. Make sure your ground wire is clean and tight too. can't hurt to pull it all back off again and be sure all is aligned and connected. An impact screw driver with a #3 phillips tip is handy here. I'm talking about the type of screwdriver that you hit with a hammer to break loose stubborn screws with. I also have installed new plugs that would not fire, not often, but be careful ruling out stuf that you already have been over. There's lots of threads about testing the coil and stators too
