Hi fellow listers,
Following up on the earlier posting about upgrading the LBC's cooling
fan (and not being worried about keeping my car original) I just
adapted an off-the-shelf, 15" diameter 6 blade stainless steel flex fan
to the ole TR4. I imagine you could do something similar to adapt or
create an adapter for another style fan.
The first modification needed was to cut 5/8" off the back side of the
fan to get clearance at the frame/suspension cross tube. The blades are
pretty deep, so this wasn't a big loss. The handy dandy Dremel tool with
those little cutoff wheels zipped through the stainless steel blades.
Biggest problem was enlarging the center bore (where the crank bolt
goes). Modern standard is about 3/4". The TR is about 1-3/16". I
carefully positioned a scrap of aluminum and bolted it to the fan, then
drilled a 1/4" pilot hole precisely in the middle. This served as a
pilot hole for a carbide cutter to enlarge the hole to about 1-1/8". I
then cleaned up the hole with the Dremel and those cute little grinding
tips. Next, a 1" drum sander gradually enlarged and trued up the hole
to just fit over the crank bolt. Finally, the fan extension itself
provided a guide to mark and drill 4 new bolt holes, offset from the
elongated "universal" holes already in the fan.
As an alternative to all the above, I imagine you could make an aluminum
spacer that would move the fan closer to the radiator and compensate for
the center bore and bolt hole differences.
I'll have the whole unit balanced when I have the rest of the crankshaft
assembly balanced, unless I can figure out a good way to do it myself.
Looks great and with about double the total blade area and much deeper
offset, I guess-timate I'll get about double the air pulled through the
radiator at idle speeds. Plus, the blades will "feather" at higher RPMs,
somewhat reducing drag on the engine.
San Jose, Calif.
'62 TR4 #CT17602
Disclaimer: I have no financial interest in Dremel or Flex Fans, just a
big one in a TR.