219
8.
Press the pulley with the new bearing into the idler arm.
9.
Do not peen this bearing onto the arm. It will break. TIG weld it into place-- it can always be
drilled out if it fails again.
10.
Cut the long end of the bearing shaft as close as possible to the outer race of the bearing and dress
it .
11.
Install your new idler.”
Of course, welding is not likely to be good for the seals and lubricants within that bearing or the temper of the shaft --
and would be especially difficult if the arm is aluminum. Perhaps while the machinist is working on dressing that shaft,
he can provide a retention scheme -- like threading it for a nut.
Note that the fan clears the front of this assembly by only a small amount, so it may be advisable to check the clearance
of the new assembly by spinning the fan around by hand before starting the engine.
This may start sounding like a broken record, but rather than repair the idler bearing, you might consider tossing the
entire engine-driven fan scheme and installing an electric fan as described below.
ELECTRIC FAN SUBSTITUTION FOR BELT-DRIVEN FAN: The best solution for fan clutch problems, cracked
fan blade problems, and idler arm problems is to install a large electric fan (or two large electric fans) and remove the
fan, clutch, mounting assembly (shaft & bearings), belt, and idler pulley altogether -- and perhaps the little stock electric
fan as well. The Jag V12 is a hot beast, so the biggest electric fans that will fit should be used; a single 16”, dual 14”s,
etc. One benefit: we have all heard stories about how much power the belt-driven fan uses or even how much the belt
itself uses, but the 16” electric fans typically draw about 10 amps -- meaning they use only about 1/8 horsepower when
they are on. And if you control them properly, they’re not on when not needed.
There are lots of places to purchase electric fans. Most local auto parts stores carry them, as well as J. C. Whitney
(page 691). Some of the best selections are from Jeg’s (page 714) or Summit Racing (page 717). Harry Trafford points
out there are at least two retailers on the www that specialize in electric fans:
Fluidyne:
http://www.fluidyne.com/
Scott's
Fans:
http://home.earthlink.net/~scottsfans/
1-800-544-5596
If you are shopping for a new fan, note that the Imperial brand electric fans are reportedly unreliable; you’d be well
advised to avoid that make. Ed Hyatt: “I have had two Imperials fail and the problem was the glue that they use to
hold the magnets to the case. The glue fails and the magnet attaches itself to the rotor, shorting out everything and
blowing the fuse.”
Also note that Hayden 16” fans come in two models, one with considerably higher airflow than the other. The high
airflow model has comparable airflow to most other aftermarket 16” fans, but is more expensive than most. The lower
airflow model is comparably priced with the others, but its airflow is pathetic by comparison. Haydens are reportedly
very quiet, though, perhaps due to their sickle-shaped blades. One more concern here is that the two different models
are visually almost identical, and on store shelves it’s entirely possible that someone has switched fans around in the
boxes in order to get the high airflow fan for the lower price -- leaving you to pay the higher price for the low airflow
model without even knowing you’re getting gypped.
One thing to look for in electric fans: a grille to keep your fingers out of it. Some have it, some don’t. If you’re the
kind of person that worries about such things, you might want the grille. The rest of us most definitely do not want the
grille, since it reduces the airflow by a considerable amount.
Peter Cohen offers another possibility: “Went shopping in the wrecking yard the other day. I came home with a 16"
electric fan from an '83 Buick Regal ($20). This fan has a ring on the outer edge that is attached to the fan blades, and
rotates with it. It is secured by three metal rods that go from the motor housing to two points on the lower radiator
support brace, and one to the upper support brace. Interestingly, it also uses a ballast resistor, and 3 wires. One wire is
ground, one goes through the ballast resistor, and one bypasses the ballast resistor, presumably to make a two speed