Dave Plowman (News) wrote:

If you made two engines identical - apart from one having ally block
and head while the other cast iron - which would warm up fastest after
a cold start?

Aluminium is a better conductor of heat, so presumably the coolant used
for the ally block would would warm up quicker. But if they were
air-cooled engines, heat would be lost quicker to the air from the ally
block.

http://www.engineeringtoolbox.com/th...als-d_858.html

Water cooled. My experience of ally engines says they are slower to warm
up. Of course newer ones will have a much lower water content than older
designs and many newer designs use some if not all ally. Hence the
theoretical question.

I suppose there could still be a large degree of air cooling going on,
even with a water cooled engine. So even if heat is conducted quicker
into the coolant, this is balanced by more heat being lost to the air.
Or something...