> Going on this thread it is suggested that the stock fan fitted correctly
> blows air in the direction of the engine. Am I just dim or is it not the
> purpose of the fan more to cool the water in the rad than cool the engine
> directly.?
> John
> --
>
The purpose of the stock, mechanical fan is to move air through the
radiator, which it does by pulling the air through the rad and pushing it
past the engine. If the car were stationary, it wouln't matter whether the
fan pushed or pulled, but as soon as the car starts to move, air moves
through the rad in the direction of the engine, so the fan is designed to
assist that natural movement. In fact, at highway speeds, the fan
contributes little to this movement, which is why most electric fans have
thermostatic switches to control them. For cars so equipped, all the engine
cooling is provided by the natural air movement at highway speeds and the
thermostatic switch will shut the electric fan off.
Electric fans are designated as "pullers", which are mounted between the
radiator and the engine, and "pushers", which are mounted in front of the
radiator. In both cases, they move air through the radiator towards the
engine, thus aiding the natural movement of air. For such fans, it is
important to ensure that they are rotating in the correct direction, because
a pusher can become a puller, albeit an inefficient one, when rotating
backwards.
Also, to clarify some of the previous mailings on this topic, for a stock
mechanical fan, the fan should be mounted with the concave side of the fan
blades towards the engine for most efficient operation. If the fan is
mounted the other way round, it will still pull air through the radiaotor
but will do so less efficiently, by which I mean that the volume of air
moved at a particular engine speed will be reduced when compared with a
correctly mounted fan. These fans were not that efficient, anyway, so you
may not notice the difference, especially at speeds, but you might notice a
tendency to run hotter at low speeds.
Michael Marr
1960 TR3A
Naperville, IL
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