Follow-up to my first post: We’ve sourced US-made M24 x 90 bolts from our local Fastenal and turned them on the lathe to match the reduced-shank profile of the Wartsila bolts.
After having 2 of the OEM bolts snap off in service and forced units offline, we decided the OEM bolts were unreliable and sought alternatives. And yes, these were all hand-torqued to spec.
Dave Mordecai
City of Tallahassee Hopkins Station