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Electric fans - Kenlowe vs. Hayden?

To: triumphs@Autox.Team.Net
Subject: Electric fans - Kenlowe vs. Hayden?
From: cak@dimebank.com (Chris Kantarjiev)
Date: Tue, 20 May 1997 12:28:23 -0700
In my opinion - neither. They are both overpriced.

I've homebrewed three electric fan installations - for a TR4A, a GT6+
and most recently a Morris Minor. I wrote about some of my experiences
a few years back; I think that message is still circulating. You can do
it yourself, do a better job, and do it more cheaply.

Contact Scotts Manufacturing - find their information in the monster
list, www.dimebank.com/monster -  and give them a call. They offer a
wide variety of sizes, thicknesses and fan blade styles. Ask for a data
sheet, and get out your ruler.  Figure out where you can stick a fan
and how big it can be. Ideally, you want a puller - that is, a fan that
sits behind the radiator core - because it is more efficient and allows
the incoming air to flow through the radiator. A pusher, mounted on the
front, blocks much of the airflow, so the fan will have to run more
often. Unfortunately, it is often not possible to mount a fan behind.
The selection from Scotts makes this more unlikely.  They have a "super
high efficiency" blade design which is just the thing for our cars.

Adjustable thermostats seem like a good idea, but for the most part
they seem like overkill, and another source of failure. I did the
Triumphs with adjustable units - they have failed, they are sensitive
to bad grounds (and the failure mode for a bad ground is to run all the
time - so I'd come out to a car with a dead battery!), and the
adjustability is not *that* useful. If your cooling system is marginal,
such as the GT6, you might find the adjustability nice to tweak the
temps high enough that the fan isn't running all the time. In general,
I mount the sensor near the bottom of the core and adjust to have the
fan come on when the temp is about 185 degF; the logic behind this is
that you want the fan on when the radiator isn't doing a good enough
job, which is indicated by the bottom being too hot.

The non-adjustable sensor (typically spliced into the ground lead) can
be used similarly - you just change its mounting position up and down
the core until it does what you want. Not as convenient, but much
simpler once it's complete. (Truth be told, I mounted the Morris's
non-adjustable sensor in the upper corner of the core, per the
instructions, and it seems to work just fine, too.)

If you look at 

        http://www.dimebank.com/Bubbaspec.html
and especially
        http://www.dimebank.com/images/bubba/fan.jpg

you'll see how I have mounted the fan directly to the radiator frame.
This is the right way to do it. Don't use the "zip ties" that are
commonly sold for this purpose - they put too much stress on the core.
If you don't care to fab the brackets and get them brazed on, Scotts
will sell you some adjustable brackets that you can mount with screws;
they probably work fine. The goal is to mount the fan firmly and flush
with the core - to avoid air "sneaking around" the edge of the molded-in
shroud. You want all the air to go *through* the core.

I wired the first car I did with a remote switch; it seemed like a neat idea. 
It's mostly a nuisance, requiring a lot of extra wiring and work to make
it look neat. I like the fact that I rigged the switch to illuminate when the
fan comes on, because it let me learn how and when it works - but you
can also tell that from the ammeter. I didn't bother on the other cars, 
and don't see any reason to do it in the future. 

I prefer to get my power from a circuit that's always hot; either brown
(in which case I use an additional inline fuse) or purple (which is
already fused - this can be a problem if your horns are on that circuit
and they take an appreciable amount of current). Some folks may prefer
the additional safety factor of having the fan shut off when the
ignition is off; in that case, wire from white (with your own fuse) or
green. I don't like putting more current through the ignition switch
than I have to, and I like the idea that the engine gets a chance to
cool off as much as it should when I shut down.

By the way, that's an advantage of putting the sensor at the top of the
core - after shut down, the entire core is cooled to the shutoff temp
rather than just the bottom.

It is admittedly more work to do it yourself. But you get a custom job
that fits just right for your application, and you can save some money
in the process. The Kenlowe installations require that you mount the
brackets somewhere on the frame and I detest the sensor mechanism that
they use (with a fragile capillary bulb that goes into the top hose).
And isn't doing it yourself part of why we own our cars?

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