Alternator Charge Wire Replacement

[Aerocoupe 11]

Working on a 69 with a 351W stroked to a 408 with only the MSD and Taurus fan to contend with electrically. The car does not have A/C and no serious sound system. It has a brand new 60A alternator of the stock configuration and I think that the stock wire from the charging post on the back of the alternator is too small diameter wise. I believe the wire that is attached to the charging post on the back of the alternator goes into the harness and is spliced into a couple of wires of which one puts power to the fuse block and I assume another goes back to the post on the battery side of the starter solenoid. Can I simply remove the wire off the back of the alternator and cut it back to that splice? From there I want to install an 8 ga. wire from the charnging post on the back of the alternator to the post on the battery side of the starter solenoid. Everything is okay right now but I think this will help the fan and MSD and keep the battery charged.

 

Any thoughts are welcomed. We talked over installing a 3G alternator but at this point there is no need for anything more than the 60A stocker.

 

Darren

[LindenBruce 27]

Sure you could do that. Run a separate wire from the batt side of the alternator directly to the splice in the engine bay harness. The splice is below the regulator. You would have to peel back the tape to make the mod. Just be sure and get everything taped back up and insulated. Bruce

[Grabber70Mach 107]

Interesting reading............

 

Taurus and Mark VIII fan Relay Kit

 

This page is intended to clear up some misconceptions of the Taurus and Mark VIII fan and relay requirements. Since the launch of our new Taurus Mark VIII Relay kit I have been ask numerous times if the 60 amp relays are high enough amperage, if the wire gage is heavy enough. Will a 50 amp fuse work without blowing. I'll try to shed some light on this subject. Let’s start with the Taurus fan.

 

There are about a dozen Taurus fan versions for the Taurus/Sable and over the years Ford and the aftermarket have made changes to lower cost and increase durability. This label of Taurus that covers maybe 10 different versions leads to most of the confusion about the fan. Some of the Taurus/Sable fans use the Lincoln motor but most do not and no Taurus/Sable fans use a Mark VIII motor. If you want to find out what motor you have find the RF number like RF24, RF123, RF64 and so on or get the part number, something like F7LZ8C607 AA then look it up on Rock Auto.

 

With that said the Lincoln and Taurus/Sable fans are not the only high CFM fans Ford made, mine is from a 95 Cougar RX7 which is a RF24. It’s a cross between the Lincoln Mark VIII and a Taurus. It has the Mark VIII blades and a motor more like a Taurus/Sable fan.

 

The RF125 fan fits Taurus, Sable, and Lincoln Continental. So in that respect a Lincoln motor is used in a Taurus fan but it’s not a Lincoln Mark VIII motor. On a RF123 which is the true Lincoln Mark VIII fan the fan motor only fits this fan from 93-96 and does not fit any Taurus/Sable/Continental housings.

 

Fan Amps:

The Mark VIII is a bigger motor and draws more amps but I have yet to see anything above 45 amps even on an old fan when it’s running. It does have a momentary spike but again I have yet to see the 100 amps I hear about.

Our testing showed the Mark VIII fan ran 26-28 amps on low, with a 37-40 amp startup spike. On high it had a draw of about 32-35 amps with a 48-53 amp startup spike. This is tested with our relay kit wired with the step through configuration and a new fan. A startup from dead stop to high speed will draw higher amps.

The Taurus fan ran 24-26 amps on low, with a 32 amp startup spike

Then on high it used about 28-29 amps with a 40-45 amp startup spike. Again wired with our relay kit and a new fan.

 

Wire:

The wire gage is important with these high amp draw accessories so I will explain as best I can on what gage can handle what amps over what distance. For the Cobra Kit, which has the longest wires, the wire is an SXL grade automotive wire. SXL refers to the insulation which is cross linked polyethylene insulation capable of up to a constant 257 degrees. It also does not burn like GPT or lower grade automotive primary wire. You can hold a match to SXL and it may char but it won't burn and drip off like the other grades.

Most all the wire lengths for the Cobra kit are less than 5 feet. The sensor wire are longer but are be cut to fit and end up much shorter than the 10 feet supplied with the kit.

 

The #10 battery wire to the fuse is 24" and from fuse to relay block is up to 5 feet, which is just at the 2% drop limit at 12V 50 amps, but remember we are under 30 amps with this fan. So if your charging system is working as it should 13.4 -14.4 you would drop .25 volts over 5 feet. This wire is also cut to fit so the drop may be less.

 

The #12 fan wires are 5 feet long which is within the max length at 40 amps, but again we are at 30 amp with this fan. The Taurus/Sable fan runs on high at 30 amps. We can run 50 amps over a 12 gage wire for 10 feet and we are well under that limit.

 

The #14 Sensor wires carry about 7 amps max so there is no issue there even at 10 feet.

 

Relays:

The Beuler relays are 60 amp relays with AGSNO contacts and Negative Spike Suppression. They can handle a spike load of 150 amps and since the Taurus/Sable fan only uses 40 at startup there is no issue with the relay loads.

 

Fuse:

The 50 amp fuse is a slow blow type fuse so it can take surges of the Mark VIII fan and not pop. It will pop on a dead short just like any other fuse. 50 amps is about 10% above the max load of the Taurus/Sable fan so it’s not an issue either.

 

Fans:

As I said before there are a lot of different fans for Taurus/Sable, Lincoln and other Ford cars. Trying to track down the various versions can be a task in itself. They have a 2 speed, a fixed speed and a variable speed fan

 

Fan Specs:

RF24 fits a Thunderbird LX and a Cougar RX7 94-97 the motor in this fan only fits this fan no other models it has 3 terminals and is a 2 speed fan with low being 1350 RPM and high being 1780 RPM. The CFM is unknown. It measures 18.5 x 24 x 5.5 deep. The Ford part number was F4SH8C607AA it is now F4SZ8C607D.

 

If you would like to add fan part numbers and Specs that you know to be right because you have one and it works email them to me at info@thoroco.com and I'll post it here

 

 

 

I found it here.......

 

 

http://www.thehollisterroadcompany.com/TaurusMarkVIIIrelay.html

 

Also if you plan on upgrading your lighting (halogen), I would rethink about upgrading your alternaror to the 3G.

Edited January 18, 2012 by Grabber70Mach

[danno 128]

That is a good article inserted by Grabber. I think there is a much easier solution for your problem. Without the fan, you really have no special load rerequirements for the factory wires and alternator. The factory cars used the same wires with and without air conditioning, and if you do not have that you should be in fine shape. Changing the wire will not make any difference to the MSD ignition. You can verify this by driving a bit with the radiator fan disconnected and then drive with it connected. You will not notice any difference.

 

I assume you are using a relay with your fan to turn it on. The simple solution you could certainly use is to connect your relay feed wire to your alternator, not the battery. You might think the fan is getting it's voltage from the battery, but when the engine is running, it is not. It is getting it's voltage from the alternator. It gets its voltage from the battery when the motor is off, but when the motor is off, so will be the fan (99% of the time).

 

If your fan does not draw much power from the car, like 10 amps, then none of this is necessary. The factory wires are fine.

[rajonmestra 10]

Working on a 69 with a 351W stroked to a 408 with only the MSD and Taurus fan to contend with electrically. The car does not have A/C and no serious sound system. It has a brand new 60A alternator of the stock configuration and I think that the stock wire from the charging post on the back of the alternator is too small diameter wise. I believe the wire that is attached to the charging post on the back of the alternator goes into the harness and is spliced into a couple of wires of which one puts power to the fuse block and I assume another goes back to the post on the battery side of the starter solenoid. Can I simply remove the wire off the back of the alternator and cut it back to that splice? From there I want to install an 8 ga. wire from the charnging post on the back of the alternator to the post on the battery side of the starter solenoid. Everything is okay right now but I think this will help the fan and MSD and keep the battery charged.

 

Any thoughts are welcomed. We talked over installing a 3G alternator but at this point there is no need for anything more than the 60A stocker.

 

Darren

 

This is actually just half the job. I recently discovered that When you add a high power sound system, you need to upgrade all of the associated alternator wiring, engine grounding, and battery which is another thing related to this issue.Anyway, there are a lot of stocks that could fit older mustangs just like the one most of us were driving.

[buening 63]

Leave the stock wire hooked up to the positive battery post on the solenoid (black), as it indeed feeds the fuse box. With my 3g, I ran a larger charge wire from the alternator to the positive battery post on the solenoid and did not use the stock charge wire. By doing this, the charge still goes to the battery and then the demand from the fuse box is pulled from the stock wire at that same location. With a short run a #6 is recommended IIRC.

 

I'd add a separate fuse box under the hood for your fan and ignition. What are you using to control the Taurus fan? I'm running the DC Controls 50a PWM controller and am pleased with it.