Tony:
Several threads in the past on
oil temp. and
oil coolers. A search should net you a number of discussions.
On a basic level you want your
oil to get hot enough to outgas some of the contaminants that accumulate and evaporate any moisture that has condensed in the oil due to heating and cooling. This equates to about 210 degrees.
Oil coolers used on street cars tend to keep the oil too cool so a number of people are running thermostats on their coolers to keep the temperatures up to the point they need.
DonC