TRB Crankshaft End Play why?

[Thob]

I would expect the crankcase to expand as it heats up as well, so calculating the crank shaft expansion may not be enough.

Instead, why not measure it?  Then we don't have to keep guessing.  Measure it cold, then run the engine and measure it hot.  You might even stop the engine as it's warming up and take a couple of measurements.  Reality always beats my theories!