Thanks!
The water test.
Mounted an empty crank case, it needed a little bit more than 400cc of water to fill it up (the case is 550cc). I expect that about 380cc of oil is needed to fill it up with a to break-in engine. So a 350cc fill marking has to be created and a yet to create small filling tube or nipple to fill it up to the right level.
Heating it up to 80 degrees Celcius takes about 20 minuts. OK, not realy fast but for sure good enough.
100 degrees celcius is reachable, on the side of the front bearing it will be about 84. At 80 degrees on the top of the crankcase it will be at the front bearing about 70 degrees. The heat is spreaded very well.
And yes, at 100 degrees the water is really boiling, time to throw in some eggs