Re: [alfa] Electric fan for 86 Spider

["Dean W. Cains" <dwc@xxxxxx>]

Hi Mark:

There are a few things to consider when installing an electric fan on your 
Spider.  The first is that you likely won't find one to fit in the less 
than 2.5" between the nose of the water pump and the radiator core.  The 
other consideration is one that I didn't expect, but it happened when I 
tried to install an electric fan on my '87 Spider, in pusher 
configuration.  The OEM radiator core was much too dense for the fan to 
push any air through.  Even using a 12" Perma-Cool fan, rated at something 
like 1400cfm, nothing but the slightest wisp of air would pass through the 
core, which certainly wouldn't cool the engine on any day here in 
Florida  (and, yes the fan was wired and oriented properly).

So, why did the same exact fan installation work perfectly on my '74 
Spider?  The '74 has a re-cored radiator (2-row), and it's very much less 
dense, both in the case of the coolant tubes and fins.  The front-mounted 
fan on that radiator blows more than enough air forcefully through the 
core, and even on a 110 degree day, sitting in heavy traffic, the coolant 
temp stays at 190F.  FWIW, that Spider has a thermo-switch (on at 185, off 
at 170) mounted in a threaded bung in the lower tank, which after several 
experiments, seems to be the ideal setup.  For my '87, I compromised and 
ended up with a pump-mounted Euro fan, which has blades with less pitch 
than the US fan, and it works just fine, too, with or without the shroud.

I've attached a pic of each of my radiators, the re-core from the '74 and 
the almost-new OEM from the '87, so you can see the differences in core 
design and density.  The quickest way to tell them apart is that the OEM 
has fins that run horizontally (maybe 22 per vertical inch), while the 
re-core has zig-zag fins that run vertically between the coolant 
tubes.  I'll bet the OEM must have several times more surface area, and 
almost twice the number of coolant tubes, but the 105/115's were always 
known to have an overbuilt cooling system.  Even so, the re-cores I've had, 
either 2 or 3 row, have always worked well enough, but must have much less 
reserve capacity.  Sorry the Digesters can't see the pics, but I can email 
them to anyone that wants them, and the files are very small.

Regards,

Dean
Lutz, FL
'74 & '87 Spider's Veloce


At 07:15 PM 12/8/2004, you wrote:
>Date: Wed, 08 Dec 2004 19:42:24 +0000
>From: "M Smith" <gtv684@domain.elided>
>Subject: [alfa] Electric fan for 86 Spider
>
>My 86 Spider is apart for a clutch replacement and seein' as it has a few
>modifications (It has Sperry Stage 3 heads, Shankle 7L cams and headers,
>Jacobs ignition, bunch of poly bushings with konis and sport springs, some
>other things I don't remember... ) I thought this would be a good time to
>add an electric fan. My question is.....Which One?
>I would prefer something that mounts to the existing shroud mounts and is
>fairly simple to wire up.
>
>Any suggestions?
>
>
>Mark in Kentucky
>86 Spider
>84 GTV6
>78 Sport Sedan

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