On Wed, 2011-07-20 at 15:38 -0700, Jake de Villiers wrote:

> When I reached out on a 98 degree F. afternoon and shot the black
> asphalt roadway with my IR temp gun it read around 140 degrees - if
> the air going past your sump is 98 and the roadway is 140, that's
> still a useful differential from your 220 degree oil, is it not?

I dunno. It depends, I suppose, on the size of the sump "heat sink," and
how much convective and radiative heat loss such a sump would show in
those conditions. I don't have any background in engine thermal
management to know how many degrees of cooling that offers! My heat
sinking background is in electronics, using passive (natural convection)
heatsinks to get rid of a few dozen watts of power. You may be right --
it could suck a lot of heat out the oil.

>
> My point about the RPM is that a relaxed climb at 3200 won't be
> building heat in the engine like 3800 RPM will - that's all. I found
> that we could climb longer and cooler at 25 MPH in second gear in the
> '84 - it took longer but the van was much happier.

Well I'll sure try that next time. Though the grades that really cause
me to sweat are the long ones which are too steep for second gear. So
the slower I go, the slower the air blowing across the sump. Same for
this external oil cooler I put on -- it has no fan, depends on air
coming down the side vent, so slow travel means low airflow.

-- RJS