It will run again

Wouldn't it be easier to replace the spline? There is already a center hole in the broken crank so it should be a simple job to drill and tap the crank. Mount another crank in your lathe by the rear bearing journal, turn the front bearing journal down and thread it to match. If you cut the thread on your lathe you can make it a slight interference fit and assemble by heating the crank and chilling the spline section. Or make a snug fit and use Loctite.

Just watching, this is outside of my skill set. We've got some ingenious dudes around here.
Rusty

RknRusty wrote:Just watching, this is outside of my skill set. We've got some ingenious dudes around here.
Rusty

lol.
Yes there are.

Been playing around with a x/y table on my drill press. Old factory drill press that I replaced the spindle bearings on.

You could cryo treat it after finish. Had several cylinder liners and cranks done this way with some of my .21 Italian race motors. Was a group buy-in. It was almost like having them super re-chromed,,the cranks didn't scratch at all and I put gallons across them. It seemed to make the ABC liners resist rapid heat changes which allowed us to run leaner needles for more time per tank. Heat gun showed a slower temp climb during race conditions as the tanks leaned/emptied.

Travis had a used crankshaft for sale so I bought that basically for the same price as all of the tooling would have cost to drill the hardened crank. In a way I cheated but it will run again.