Gerry commented on my reply to the too-cool oil cooler question:
>I have read in several books that oil contributes to about 30% of the cooling
>for a water-cooled engine (higher for an air-cooled engine). Therefore
>having an oil cooler will help with engine cooling.
>
>This is escpecially true in a high performance arena. From personal experience
>I have noticed a drop in water temperature after fitment of a bigger oil cooler
>to both by pro-rally cars.
>
>gerry
But it is true that the primary purpose of an oil cooler is to maintain
optimum lubrication by keeping the oil viscous, not to cool the engine.
If all one desired was a 30% increase in cooling capacity, it would be
easier to fit a 30% larger radiator than to install an entirely independent
cooling system for the oil.
Of course, extracting heat from the engine by any means and depositing it
in the air will provide cooling. But in an engine operating within its
normal temperature range, the thermostat would compensate for this by
closing slightly to keep the temperature up to the operating point. The
only way an oil cooler should produce a drop in engine temperature is if
the capacity of the cooling system, at the thermostat's set point, is
exceeded by the heat output of the engine. This forces the coolant
temperature beyond the set point, where it is amenable to the cooling
effects of oil coolers, lower ambient temperatures (or even a quart of
Fosters* poured over the radiator). Presumably this is the situation for
your pro-rally cars.
Because it's dumping heat, an oil cooler will delay initial engine warm-up,
however. Which is why I sent the addendum to my initial posting on this
subject (Majordomo somehow delievered these in reverse order - sorry) about
blocking the oiler cooler when it's very cold.
BTW, that cooler cozy Bill Mills mentioned sounds neat! (It would have
been a natural product for the MG Mitten company to handle. Anyone else
remember them?)
Russ (almost warmed up today) Wilson
*Why is there so much recent chatter about Fosters? What happened to the
Old Speckeled Hen thread....?
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