[Joel Koontz]

LouisianaGuy, I do not think you would get any benefit from creating a larger shroud. Getting the existing shroud to seal well would be more important. A larger shroud might actually be a negative as it would restrict more air when the fan is not running.

I have been running a Mark VIII fan for several years now and it seems to work fine with the existing fan shroud just covering part of the radiator on my 68. I have mine on a thermostat and going down the highway my fan virtually never runs at all. When it comes on while stopped it does not take long to cool down and cycle the fan off.

To seal mine to radiator I cut a slot down the side of some vacuum hose and used it as a cushion where it is up against the radiator.

Bigred455, I have read that running two relays is not the best arrangement. Better to use one relay of adequate size. If a relay is too small it will eventually fail reguardless of how many you use. Two does give you some redundancy which may delay having a breakdown, but from what I read, one of the relays will alway trigger slightly quicker than the other and for an instant take all of the load(load is by far the greatest at start up) causing it to eventually fail. Then your down to one and probably won't know it till the second one fails also.

I am using a 75 amp relay, but I forget right now the brand, or where I got them from. It seems to be working fine.


Sporter, I have also read that the Ford Solenoid is designed for short term intermitent use only and is not appropriate for continuous duty use as this would be.

After I installed mine I noticed some relays in a parts store that were intended for a snow plow. It specifically stated on the packaging that they were for continuous duty use. I have not tried them since mine is working fine but if I had to replace mine for some reason I think i would try one of these as they seemed to be heavy duty and had a high amp rating.

Please note the I am not tyring to claim that I am any type of electrical expert. I am just relaying what I have read in hopes it will help others. Before I installed mine I did a bunch of research. There is a lot of info on the Mark VIII and Windstar fans on the Chevelle Tech site and I would suggest doing a search there.

[Blue '66]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Joel Koontz:
I am just relaying what I have read in hopes it will help others. Before I installed mine I did a bunch of research. There is a lot of info on the Mark VIII and Windstar fans on the Chevelle Tech site and I would suggest doing a search there. </div></BLOCKQUOTE>

Thanks,I want to read up.Is it Chevelle.com?


What size alts do you need to run W/ the electric fans?

[68GTOKeith]

http://www.geocities.com/diels12000/WindstarFans.html I believe this is the site. Lots of other information as well. Keith

[LouisianaGuy]

I think the mark 8 fan is a 2 speed unit?? anyone know fer sure.
Mike

[LouisianaGuy]

Ok this Mark 8 fan has 3 wires on it, one blue and two black...Is this thing a 2 speed unit?
Mike

[Sporter]

I run a factory Ford connector with 2 red wires and 1 black wire. Middle connector is a dummy.

[firechickenman]

Mike -

From what I could tell from the wiring diagrams, the Mark VIII fans are variable speed and controlled by a module. You're only going to have high speed. The newer models have 2 wires - light blue and black. The older ones have 3 wires - light blue, black, and one wire that the color was not specified (it says that wire is unused and ends in the harness). Light blue is power, black is ground, and the other black??? Are the 2 black wires the same gauge? If they're not, then the larger one is the gound wire.

[LouisianaGuy]

Ok did some testing with my battery charger and Mark XIII fan
It seems that the black wire to the right is neg and the blue wire on left is pos, and the other black wire in the center does squat, least it only lugged the fan down when Connectewd with the other black wire.
Man this thing pulls major air at 115 amps on the batter charger, I laid it face down on the dround and could hardly lift it due to the sucking force.
Even at 35 amps and 12V this thing is amazingly powerful. I really dont know if I need an extra shroud around the end of this fan, I am going to go ahead and finish making it then just add the fan with out the larger shroud and try it.
Gota get a temp switch tomorrow then finsish installing and wiring wiring it and I will post the results tomorrow on how well it cools with a 29 year old radiator :P
Thnaks sporter, it was actually labled on the fan but had to clean it to see it LOL.
Chicken the black wires are both the same size, and like I said if i ground it with the other black wire it lugs the fan down, and if I use just the fdummy and power wire it just sucks juice and the fan does not move....Wonder what its for, it ran up into the wiring harness in the car...I may ride out there and check it out tomorrow.
Im assuming htat these relays I pulled from under the hood will work since one of them did come off of the Hole marked FAN lol, I found a website that said the fan pulls 33 amps continous and 100 amps on start up. I would think with a 100 amp fire off it would pop the relay right off, Im just going to wire it up and see what happens...Sporter I hope that new 100 amp alt will do the trick :P I know my power windows barley even pull on the guage now when I hit the switch
Mike

[Joel Koontz]

The website is actually teamchevelle.com and you can find the info in the Chevelle Tech forums, primarily in the Electrical Forum.

My testing also indicates that the center terminal is not used, at least on the year/model of fan that I have. Might be used on other years/models, don't know for sure.

As I mentioned previously. I think the existing fan shroud will work fine if sealed well.

I think I have a 110 amp alternator and it seems to work fine, but the fan is usually only running a small portion of the time.

See my previous comments about relays.

[rasilverbird]

Ressurecting an old post....

So running 2 relays parallel (one to each fan) was frowned on by a couple people....how about using one relay to trigger the 2nd relay? It was recommended to me by an auto parts store clerk.

[LouisianaGuy]

Ras, I finally got my electrical problem fixed and im up and running my lincoln mark XIII fan with one 30 amp relay an its working just fine.
You can pick up a relay kit at pep boys for around 50 bones , and it comes with an adjustable thermostatic control switch and pretty good instructions, altho the wire seems kinda thin for power wire it works just fine and never gets hot, Ill post pics.
I dont think anyone should have a need for dual fans to cool their engine. This one fan on my car with a 29 year old radiator that just holds water and doesnt really pass it around like it should keeps my car at a nice 180 degrees. i DIDNT EVEN HAVE TO ADD A SHROUD AROUND THE EXISTING ONE ON THE FAN.
mIKE

[rasilverbird]

Cool deal Mike....I have some fans out of a '96ish LHS, so they don't quite pull the same air as the Mark VIII unit. Hopefully I'll just need the one relay, but we'll see.

[Joel Koontz]

Ras, I don't see how using one relay to trigger another would be any benefit at all, it would in fact, make it less reliable. Each relay would pull the full amperage and if either relay failed, the fan would not run.

Lguy, yours may work for a while using a std 30 Amp Relay but you are asking for trouble. A relay is NOT like a fuse. A normal fuse that functions properly will burn out as soon as it is overloaded. If a relay is overloaded it does not normally burn out as soon as it is overloaded(unless it is hugely overloaded), it will deteriorate each time it is overloaded(and to some extent even if it is not overloaded) and will eventually fail. The more overloaded it is the faster it will fail. You might get 6 months out of it but I would not be surprised to see if fail in less than 30 days if you drive the car much. I strongly suggest you carry a spare relay in the car if you continue to use a 30 amp relay.

YOU SHOULD NOT RUN LIGHT GUAGE WIRING TO THE FAN. It should be at least 12 guage, 10 guage would be better. You can use light guage wire to trigger the relay but the main power feed to the relay and from the relay to the fan should be at least 12 guage and as short as possible to get the best performance from the fan. The ground wire should also be at least 12 guage and as short as possible.

Although I doubt(but I'm not sure) it will hurt the fan, a 16 or 18 guage wire will hinder the performance of the fan significantly. The fan will get reduced voltage and will run at reduced speed. Have you ever installed relays to improve headlight function. I have done it on a couple vehicle and it made a huge improvement. The fan draws a lot more amps than the headlights do and you need a heavy wire to get as much voltage as possible to it, to get best performance.

[LouisianaGuy]

Joel, the wire to the fans main power supply is 12 guage I think after looking at it again. Also on the package the control unit came in it said 30 amp but on the top of the relay it clearly says 40/50 amp So i think its a 40 amp, None of the wires even get remotley warm after fan was run all day today, in warm weather.
Now explain how and why you run headlights on a relay, I might do this as my headlights hit the alt almost as hard as the fan does Lol.
Mike

[Joel Koontz]

If it is a 12 guage wire and a 40+ Amp relay you will probably be OK. Still would not be a bad idea to carry a spare relay. No matter what size you use it will eventually fail. Just takes less time to fail when it is undersized.

You would wire headlights the same way you do the fan. Gets higher voltage to the headlight. Most headlights run small wire, probably 18 guage, from from the fuse panel to the headlight switch and then out to the headlights. End up with 10-20' of light guage wiring and it significantly reduces voltage to the lights.

If you want ,you can check voltage with your
current setup. Compare the voltage at the battery terminals with the voltage at the headlights. If you have 13.8 at the battery you will probably have less than 12(with old wiring probably a lot less) With relays(one for high and one for low) and heavy/short wires installed you should loose less than 1/2 volt.

I don't think it will do anything to reduce drain on alternator. I would actually expect that it might increase the drain.

I saw another post you had on alternators. I have not had good luch with ONE WIRE Alternaors. I had 2 go bad in a short period of time. Installed a late model GM alternator(forget model right now) that is around 110 Amps and it has been working fine for several years.

[ponjohn]

Anybdy use this http://www.dccontrol.com

John

[grandville455]

subscribing

[TA-71]

Glad this got brought back up. Great info here!!

[LeighP]

My set up is a Champion alloy radiator (firebird specific) set up in a custom alloy shroud/mount that I designed to suit the fan pack I'm using.
Fans are a dual set up out of an early 2000's Ford Falcon (full size sedan here in Australia)...they move a lot of air.
Controlled by a Derale adjustable controller.



Controller (top right on the rad support)

[aktattoo]

has anyone used this kit? http://www.summitracing.com/parts/HDA-3651/?rtype=10