Has anyone ever converted to electric fans who had a mechanical fan stock? How did the conversion go? I just bought an LT1 fan assembly to hopefully cool my car down better. I am mainly just wondering about the wiring. I wondering if I can get a fan switch and the the fan wiring harness from a parts car and have it work like stock. If anyone that has done it has any advice that would be cool.

 

Sure. Check the following link:

https://www.thirdgen.org/forums/cool...electrics.html

JamesC

 

It's pretty common in the street rod world.

You need a fan relay and a temp switch that you can install wherever it's convenient.

The - lead of the fan motor should go to ground, with a BIG HEAVY wire (10 gauge would be good). "Ground" should be a really large, solid place; the engine block, under a bolt head, would be a good choice. Maybe, the same place that the - batt cable goes.

You need a lead from the + side of the batt (where the + batt cable hooks to the starter is excellent) to the relay contact; again, use 10 gauge wire. It'd be a good idea to use a fuse or a fusible link, as close as possible to the power source; a fusible link can be made from wire that's 3 or 4 gauges smaller than the wire it protects, so since you're using 10 gauge wire, use a 6" - 8" piece of 14 gauge as the fusible link. The relay needs to be rated for AT LEAST 30 amps.

Then a heavy wire from the other relay contact to the + side of the motor.

On the coil side of the relay, you need switched ignition to one side of the coil; the other side of the coil to the temp switch; and the other side of the temp switch to ground. There's very little current in this circuit (that being the point of a relay.... control is low power, output is high power), so you can use small wire, like 18 gauge or 20 gauge. If you use a factory style switch it will have only one lead, the case is grounded by screwing it into the motor, so you don't need a separate ground. The switch needs to be on the hot side of the cooling system: either in the head like the factory does, or in the intake manifold crossover passage, or in the water outlet. You can buy a new water outlet for pennies at the parts store, if you don't have a hole in yours to use.

If you have A/C, you'll want the fan to run any time it's on, otherwise it won't cool hardly at all at low speeds. Easiest way to do that is to add a high-pressure switch at the high-side Schrader valve. Needs to be a normally open switch that closes at about 200 psi. Wire one side to ground, and the other side to the same place on the relay that the temp switch goes. What you want is an either/or operation: you want the fan on if either the temp is above the switch setting, or if the A/C is operating (compressor is generating pressure).

IMO it's probably easier to add that little bit of wire and stuff than it is to try to find a factory wiring harness that's unmolested, and change it all out.

I'd suggest getting rid of that LT1 fan (like, sell it to somebody with a LT1); and get the fan out of about a 90-95 F*rd Taurus or Mercury Sable or Lincoln Mark LXIV with their 3800 motor. That fan moves more air than ANY GM fan. You can get them new, shroud and all, from places like Zbra or 1AAuto, for about $100. http://yhst-12260461708320.stores.ya...ercury%20Sable Might even come with a plug, you'd have to call them and ask.

 

or you can get an later model RS camaro fan.

its a single fan, its cheap, it will bolt right up (get the shroud), looks factory, and it works...

 

I'll be damned... That's one fine post sofakingdom, you can't be that dim after all eh?
I didn't realize it was so simple... I've already upgraded to a CS144 alternator kicking out a scalding 140A, and my nylon flyswatter fans ROAR at over 2500RPM is really starting to annoy me.

How would that ford fan assembly bolt up? I'm not sure how it would attach to the rad...? Oooh, then I could get rid of the factory shroud altogether eh?

 

For the temperature switch, would an autolite 3246 work? 170*F on, 200*F off?
That seemed more desireable than 220*F on, 190*F off.
1/2" NPT ? Passenger side cylinder head would be a good place for that?

 

Yeah he makes it seem so easy. Great info though.

 

Did that, WAS cheap, DOES work. Seems like someone tossed that out as an option back when Sonix was choosing his mechanical fan...

 

hahah, oh yea! It seemed like a lot more work back then for some reason... I thought there was more wiring, etc.
I figured all those vehicles with mech fans were working fine, mine should do fine with a cheap $17 nylon fan.... Now after driving that for a while, I remember how annoying fan ROAR can be, just like on all those old '70s farm trucks...

 

Alright, no parts stores locally had the entire assembly, so I found a '95 Taurus at the wreckers with a 3.8L engine. The whole fan assembly was a scalding $19.90.
A 1989 Camaro 5.0L fan switch, set at 204-220* closed circuit was $35 at Napa, and the plug to match was $20. This is a 3/8"-18 style one.

A 30A relay was about $5, and a couple of 10' spools of 10AWG wire, terminals, and heat shrink totalled ~$15.

Here goes nothing. Lets see if I can figure out a way to mount the thing now...
oh, the ford fan has a 3 wire connector. Anyone have a wiring diagram to see what the mystery 3rd wire is? They are all 10AWG or so.

 

Ok, this is a two speed fan...
I'm going to just wire it up to the low speed, if I have cooling problems i'll swap it over to the high speed. I don't think i'll go to the trouble of using two cooling sensors and whatnot.
Apparently the low speed draws around 20A running, and high is around 35A. I'm going to use a solenoid I have lying around, so that I can use the high speed if I want to.

I also picked up some 1/8"x2" AL bar to try to make up some kind of mount for the fan.

 

Right on, this works like a hot damn.
I just drilled a hole in the top of the rad, where there's the lip, and used a single #10-24 machine screw to hold the fan to the rad. I used foam tape around the fan to give it a seal to the rad.
However, i'm using a stock fan switch from an '89 Camaro. Napa listed it as 204-220*F being the closed circuit temp. Not sure when it opens back up again.
According to my factory gauge, the fan kicks on at around 230*F or so. This is a tad high for me, since it's not exactly a stock LG4 in there anymore.
Does anyone know of a temperature switch that would fit in there, with a lower "on" temp? I skimmed through the entire NAPA catalog at their warehouse and this switch was the only one they had (looking it up by application).
I'm using a 180*F t-stat. I'm thinking a 190* switch?

 

Hey Sonix, you can use this Corvette fan switch. it turns on at 200, off at 180.

http://www.mamotorworks.com/corvette...rame=1.138.944

 

Hey! Thanks!
Hmm, that's not the factory fan switch for a '91 Corvette is it? It's an upgrade?
I was hoping to be able to buy this locally from a parts store (ie, this week), rather than having to ship it from the states, pay shipping, customs fees, etc...

 

I think it might be an upgrade. I am pretty sure the Grand National's have a low temp fan switch. Let me see if I can find the part number.

 

Sonix, Summit and Jegs stock fan switches that come on at 200 off at 185, on at 185 off at 170 etc. There are a lot of different ones out there. Jet, Painless, Hypertech make them among others. I have a jet on my `88 Iroc 383 now, works great.

 

Yea, I did find those. $40 per, and shipped out of ohio. This one for the corvette sounds about the same as the on at 200*F off at 185*F one by hypertech (4028 IIRC), but only $16.
Unfortunately i'd be looking at 1-2 weeks shipping. I was hoping I could pick one up at a parts store if it were a factory part, and put it in this week for my road trip this weekend. I guess the stock 1989 one that's in the car now should work for a while....

If no one can think of a factory car that would have that opening temp, then i'll just order the one from that corvette website.

 

[QUOTE=Sonix;3423909]Right on, this works like a hot damn.
I just drilled a hole in the top of the rad, where there's the lip, and used a single #10-24 machine screw to hold the fan to the rad. I used foam tape around the fan to give it a seal to the rad.


Can you post a pic of this?

 

I used 3/16" thick x 3/8" wide foam tape I think. It was in the window and door aisle at a home depot type of store, $4 a 25' roll. I need to use more to fill the large gap on the DS. So far i've only used it on the parts that would touch the ground if I layed the fan on a flat floor.
I used a single #10-24x1.5" long panhead robertson screw, one 3/16" washer, and one 32/16" nut (aka #10-24). Normally even I would think this is sketchy, but if I grab the fan and wiggle it, the whole thing moves, ie, rad and all. It's on there good, the foam is compressed and acts as preload.

I ordered a 200*F closed, 185* open thermal switch to replace my stock 1989 camaro one (220* closed, 205* open, or so. Temp gauge thinks it's higher than this). As well as a 3 piece air dam to replace my non existant one.
Just took a 400 mile road trip yesterday, and aside from the many other problems with this car, the cooling system was working fine.

You can see the wiring in one pic there, I used a continuous duty solenoid, and a 40A maxi fuse.
I think I might wire up the low speed fan to the 200* thermal switch, and try to put leave the 220* switch in there as well, and wire that to the high speed. I really don't think I even need high speed, but since I have all the parts, maybe....
There is a doc online showing a wiring diagram on how to wire up both, that way they won't run at the same time, etc.

 

Got the switch last night and installed it. Now it won't go over 220*F. I think the gauge reads a bit high as well. I can hear it kick on the fan as soon as it hits 220*, so either the gauge reads ~15-20* higher than it is, or the fan switch is kicking on a little late. Think this could be caused by excessive resistance in the wiring? I'm tapping off the choke wire to power the coil on the solenoid after all...

 

gauge sending unit: on the drivers side head


normal place for fan switch: lower block on passenger side.




they're both probably reading right, but the the block is cooler there then the head is..

 

Really? Huh, my fan switch is in the same place as my gauge sending unit, just on the passenger side. I thought in the lower part of the block there's just plugs? Or a knock sensor perhaps?

 

No, that's the knock sensor. The normal place for the fan switch is in the passenger side head.

 

to be honest, now that you've called me on it, my memory is to fuzzy for me to be sure.

i coulda sworn it was there, but i know the knock sensor is on the block there too... so i cant be right. LOL.



in anycase, my point is still there.. the sensor isnt in the same part of the engine as the gauge.





dammit, cant you guys talk LS1 3rdgen stuff from now on? i can recall that stuff better.. LOL.

 

The gauge sender is in the same spot as the fan switch, just on the opposite side of the engine. Both are in the heads.