Every component in an engine is manufactured to a dimensional tolerance at (21.5deg C if I remember right). So there will be variations in dimensional shrinkage depending on the bulk of each component. Effectively, nothing fits properly until working temp is reached.
The 6 P principle
Slight thread drift (and may be too modern and high-tech for Mr Farmer) but I’m using remote switching via the internet and Moes devices for a few things around the hangar and workshop. You do of course need a working WiFi set up but it makes switching things on and off from home a piece of cake. On a really cold morning I can switch the workshop heater on before I leave home and enjoy an extra productive hour when I arrive.