In a message dated 97-11-27 06:29:49 EST,
STUART_BRENNAN@HP-Andover-om3.om.hp.com writes:
<< A while back somebody said that our stock fans were located too far
into the shrouds, and that a lot of air was getting flung off the
blade tips inside and recirculating. >>
Fan Design
Rear wheel drive automotive fans act as combined axial and centrifugal fans
because the air coming into the front of the fan from the radiator must
immediately turn 90 degrees to get around the engine. In an Ideal design, the
air travels axially, with the guidance of the shroud, through the front two
thirds of the fan and then turns 90 degrees radially. To do this, the shroud
should end so that the rear third of the fan blades are exposed behind the
shroud. If the shroud covers more than two thirds of the fan, the distance
for the air to turn is shortened and the efficiency of the fan is reduced.
Relocating The Fan
Fan mounting hubs on Ford fans have a press fit on the pump shaft. The fan
can be moved rearward by removing the pump and pressing the mounting hub
further rearward on the shaft. There should be enough room to get the ideal
one third fan blade dimension in a stock Tiger. if there isn't then the
shroud must be located too far rearward.
John
Logan
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