Charlie69's 66 520 Build

[Charlie69]

I will probably have to add more relays to get what I want.  If the Volvo controller will not run both fans at the same time then I will take it out and just use a 4 relay system.  If the BMW dual temp switch only switches 1 temp at a time then I will have to use 2 separate temp switches.  This has not been tested but the Volvo controller and the BMW temp switch only cost $2 at the wrecking yard.  I had planned a Taurus s speed fan originally but could not get enough space to mount it.

[Lockleaf]

 

This is the circuit I designed that uses the bmw temp switch but runs two fans. Fan A on low temp, both fans on high temp, and when the a/c is on, overrides fan B to run full time.

 

Without the diode between the a/c switch and the temp switch for fan B, then both fans would turn on when the a/c is turned on.

 

Like this

 

 

It's been discussed quite a bit in my Half Pint thread. If it looks like it will do what you need, use it, ask any questions if I can be of help.

 

If not helping, please ignore me :)

[Charlie69]

You are helping!  Please do not stop.

 

I hope this helps.  This drawing is scaled to fit on a letter size paper 8.5" x 11" in landscape mode.

 

[Charlie69]

Both the Volvo relay and the bmw temp switch are designed around one fan capable of two speeds. So if you have it all wired together the way the Chevy guys etc. do it, then I think it will turn off fan A and turn on fan B when it goes from low to high. But if you have gotten fancy with the wiring, then no worries.

That is what I was afraid of.

[Lockleaf]

You are helping! Please do not stop.

 

I hope this helps. This drawing is scaled to fit on a letter size paper 8.5" x 11" in landscape mode.

 

Almost. The blue line should be marked low temperature, and the green line be marked high. High temp side is also a/c side.

 

And fuse ratings are currently unknown. The top fuse won't be much because it's just actuating the relays. Bottom fuse might be correct?

[Charlie69]

OK I can change it.  The fans I have only draw 10 amps each at start,  They are 12" single speed fans.  The Taurus fan draws about 40 amps at start on low from a non turning fan and on high not turning the Taurus fan will draw 60 amps,  This is not a realistic high speed start as when high speed is switched on the fan is already turning at low speed.

 

The fuse and wire gauge is up to individual need and choice.

 

[Lockleaf]

I didn't say thanks. So.

 

Thank you for drawing up a nicer version of my ghetto diagram.

[Charlie69]

I did it to share.  Down load it and save it.  If you would like it in a pdf format I can email it to you.

 

Remember I could not have drawn it with out you sharing your drawing.  Thank you for sharing.  All the dual fan setup I have seen use a third relay to do the AC circuit running both fans.  I would like both fans running on high tenp because we have some real long lights here because of trains.  But in all honesty I do not see me needing it as a seperate circuit because if I am stop in traffic waiting on a train I will have the ac running any way.  LOL

[Lockleaf]

omit the diode on the green wire and the a/c switch will run both fans. Nice and easy. Then if you decide you only want one fan running, you just splice in the diode, and you're done.

 

And yes this design runs both fans on the high temp setting. For me it's just latent overheat protection. It's not quite as warm where I live in Utah as you guys farther south :)

[Charlie69]

This what I will use instead of the fuse-able link wiring.  I get this from Nissan Quest Vans,  Not sur what year.

 

 

 

 

[Lockleaf]

Nice.

[Charlie69]

The 2 black fuses are 65 amp, the blue is 100 amp, the white is 120 amp

 

I forgot these pictures.

 

 

 

 

 

 

 

 

[gene knight]

A lot of work for a 66 datsun 520. I'm glad that it ain't me doing all this hard work

[Charlie69]

It is enjoyable work Gene.  When it is done I hope to be able to drive it like I stole it for many years. 

 

My brother was coming over to help me work on the front suspension this morning but he slipped and fell in the shower last knight and hurt his back.  He has had two major back surgeries and we are praying that this will not turn into back surgery number three.

 

I will do some work on my 520 today but I will be available in case my brother needs to go to the hospital.

[Charlie69]

I finally decided on the dual cooling fan wiring and changed the wiring diagram I am drawing for this truck.  With this the 3 relays, low temp & high temp senders both fans will come on at 185 degrees at 6volts & about half speed.  The high temp sender will engage at 195 degrees and run both fans at 12 volts and full speed.  If the temp does not reach 185 the fans will not come on.  My only concern with this wiring is will the fans get hot running at 6 volts.  This will eliminate the meed for an AC over ride circuit.  Any feedback on this wiring is appreciated.

 

 

This wiring idea came from.

 

http://www.gtsparkplugs.com/electric-fan-wiring.html

 

[S30Jay]

Nice work on the schematics Charlie! I can't say if the fans will heat up or not though..... One way to find out though.

[Charlie69]

Thank you S30Jay.  I was pretty good with electrical when I was young but as I age I seem to struggle with it more and more. 

 

Before I wire up the truck this way I will set it up as a stand alone test and check the starting & running amps at both the 6 volt and the 12 volt.  I will also let the fans fun and check the temps of the motors.  I will document this when it happens.

[S30Jay]

That sounds like a solid approach.

[LTJ]

Thank you S30Jay.  I was pretty good with electrical when I was young but as I age I seem to struggle with it more and more. 

 

Before I wire up the truck this way I will set it up as a stand alone test and check the starting & running amps at both the 6 volt and the 12 volt.  I will also let the fans fun and check the temps of the motors.  I will document this when it happens.

Looking forward to the results, the running at half volts has me intrigued!

[mklotz70]

Hi guys.  I hope Charlie doesn't mind, but he asked me in a PM to clear the 2 speed circuit up a bit.  I'm just going to copy/paste what I sent him....he may have just done the same thing.....so that the rest of you might get a bit of clarity too.  

 

Hi Charlie,

Been awhile since I had to think about anything electronic.....took me a few min to get my brain in gear.

Let's see.....the diode is optional....but if you don't put it in, then there needs to be an open there....not a connection.

 

They're using a series circuit so that the voltage is divided between the two fans.....which assumes that they're both the same resistance....in other words, a matched set of fans.  If you run two different fans, they may spin at slightly different speeds.

 

When the low temp sw turns on, it applies ground to the left relay only because of the diode(or open) stopping the ground from getting to the other two relays.  When the left relay turns on, the red wire applies 12v to pin 30....which moves thru to pin 87 since the relay is energized.  That 12v is applied to the + term of the left fan.  It goes thru the fan to pin 30 of the middle relay....which transfers it to pin 87a....which applies the voltage to the + terminal of the right fan.....which runs the fan because the fan's - terminal is ground.  The two fans are a voltage dividing circuit because they're in series.  The voltage on the + term of the right fan is also felt on pin 87 of the right relay, but since it's not energized, it doesn't do anything.

 

Basically, the middle relay switches the ground for the left fan from going straight to ground on pin 87 when energized or thru the right fan when it's de-energized.  

 

Hope that helps.  :)

Mike

 

I didn't really go over the high speed circuit.  Basically, the diode will let the ground from the high speed switch be felt on the left relay and turn it on as well.  Since all 3 relays will be on, the left fan sees a full 12v because the middle relay grounds the fan directly instead of thru the right fan.  The right fan gets 12v with the right relay energized and it is already grounded.  It's a nice circuit.  .....and that gtsparkplug site has a ton of great info!!!

[Charlie69]

Thank you Mike.  When you need clarification on a subject it is best to ask a professional.

 

With this fan wiring I see no need to ad a AC over ride circuit as the 2 hi/low temp switches will handle it fine.  This circuit has the "Blue Hands Inc" approval!

[Charlie69]

worked on my 520 today.  I finally got the old LCA bushings out.  This chassis was used daily in the Bagdad AZ open pit copper mine.  before the EPA got on the mines heavily the mines uses old acid mixture from leaching process to mix with other salvages substance to put on the roads for dust control so every thing on this chassis is rusted together.

 

Brother came by to help and he tried to drive in the right LCA B\bushing and it stopped moving about 1/2 way in.

 

Garret my brother is going to build a tool to press in the bushing this week.  Hopefully we will be able to finish the front end work next weekend.  I plan on working on the wiring this week.

[mklotz70]

Thank you Mike.  When you need clarification on a subject it is best to ask a professional.

 

With this fan wiring I see no need to ad a AC over ride circuit as the 2 hi/low temp switches will handle it fine.  This circuit has the "Blue Hands Inc" approval!

 

LOL!  Not quite sure how much that's actually worth, but you're welcome.  

 

The AC over ride is there because the condenser needs to be cooled to be effecient. If you let it wait until it's caused the radiator to get hot, the condenser will be really hot......if the fans can't cool it faster than it's being heated by the condenser, you could end up with thermal runaway.......you might want to consider one.

[gene knight]

Slowly but surely it will be ready

[Charlie69]

Mike there is a bunch of us in the Datsun and Ratsun community that value your input.  

 

No work on the 520 today, had a YAG Laser procedure done to my right eye.  I am just going to take it easy today and maybe take a nap!  LOL

 

Explains the YAG Procedure.

http://www.webmd.com/eye-health/cataracts/ndyag-laser-posterior-capsulotomy-for-cataracts