Do you have a harmonic balancer (thrust bearing type) installation tool? The type that threads into the bolt threads in the crankshaft? If so, cut yourself a piece of 1 1/4" ID pipe about 2 1/2" long to work as a spacer. Use the pipe in conjunction with the balancer tool.
1. Just warm up the crank gear in the oven (about 300 degrees for about 20 minutes).
2. Grab it with your gloved hand, line it up with the keyway and slide the gear, chamfered side first, onto the pre-oiled crankshaft nose.
3. Place the pipe between the thrust washer of the balancer tool and the gear, quickly thread the balancer tool into the crank nose, and turn the nut against the thrust washer, which pushes on the pipe and in turn pushes the pipe against the crank gear.
I hope this helps,