Rebuilt tons of them , never had one self destruct after cracking the cases if done right after cracking them. Had several grenade from the customer wanting to cut corners.
As Paul said if it has been sitting, as it looks like it has, you should open it up and clean everything, especially the sludge trap and oil passages. Check the crank and install fresh bearings. Bushings and bearings are cheap compared to the cost a blown engine.
