What happens to an engine during a cold start in sub-zero temperatures?

My truck started in 38 below F. Actual temp, not wind chill. Didn't even rattle, 5w-30 QS.

My Dad, being reared in North Dakota, used to get coals hot and when they turned white (no flame), he'd slide them under the oil pan. Warm oil, the old flat 8's would pop right off, even with 6 volt.