I want to change my external charging system to an internal style. I plan on using a conversion kit listed in the link..
https://0193647.netsolstores.com/index.asp?PageAction=VIEWPROD&ProdID=18969&strVarSel=&strCompare=

I need to run a 140 amp alternator to run a Lincoln Mark VIII fan. Do I need to upgrade the main red power wire from the alternator to the battery, if it currently is in good shape??

Thanks...

this is a partial chart from chevellestuff.com
Recommended Charging-Cable Gauge Size

AMPS To 4-ft 4-7 ft 7-10 ft 10-13 ft 13-16 ft
85-105 6 6 4 2 2
105-125 4 4 4 2 2
125-150 2 2 2 2 0

factory charge wire is only 10-guage, if your going to upgrade to this kind of set-up you should research the tech reference series on the tech tab above, and or visit the mad electrical site, ot the chevellestuff.com site, all have a lot of info on swapping altenators and wiring correctly to prevent overheating (fire) wires. i rewired the front of my car with the recommendations of the MADelectrical site and it works great like it should.....:)

this is a partial chart from chevellestuff.com
Recommended Charging-Cable Gauge Size

AMPS To 4-ft 4-7 ft 7-10 ft 10-13 ft 13-16 ft
85-105 6 6 4 2 2
105-125 4 4 4 2 2
125-150 2 2 2 2 0

factory charge wire is only 10-guage, if your going to upgrade to this kind of set-up you should research the tech reference series on the tech tab above, and or visit the mad electrical site, ot the chevellestuff.com site, all have a lot of info on swapping altenators and wiring correctly to prevent overheating (fire) wires. i rewired the front of my car with the recommendations of the MADelectrical site and it works great like it should.....:)

Vince thanks, I have been reading through some of that stuff, very informative. I am very inexperienced when it comes to wiring, so some of the stuff is over my head right now. The only power accessory I run is the fan, no ac or stereo.

If I run a 2 gauge wire, does it need to be just from the alternator to the horn relay, or all the way to the battery?? Thanks for your help...

Vince thanks, I have been reading through some of that stuff, very informative. I am very inexperienced when it comes to wiring, so some of the stuff is over my head right now. The only power accessory I run is the fan, no ac or stereo.

If I run a 2 gauge wire, does it need to be just from the alternator to the horn relay, or all the way to the battery?? Thanks for your help...

:confused: it depends on where the battery is located and if you have (f*rd) solenoid in the starting system or just the regular gm-starter-solenoid set-up. also depends on if you have the short or long water pump set-up for which side of the engine the altenator is attached and if you will be running the power from the horn relay to the FAN-relay to provide power to the fans.....:yes:

:confused: it depends on where the battery is located and if you have (f*rd) solenoid in the starting system or just the regular gm-starter-solenoid set-up. also depends on if you have the short or long water pump set-up for which side of the engine the altenator is attached and if you will be running the power from the horn relay to the FAN-relay to provide power to the fans.....:yes:

Battery is located up front, I do not run a solenoid, and its a long water pump, alt is on passenger side.

Here is how the fan is wired. I added an 60 amp fuse with 8 gauge wire from the fan to the relay and the relay to the battery..
http://www.chevelles.com/showroom/data/500/dia-1.jpg

Just curious on MAD they only use an 8 gauge wire, but that chart shows to use a 2 gauge wire for 140 amps??? AM I missing something here???

Thanks again....

Battery is located up front, I do not run a solenoid, and its a long water pump, alt is on passenger side.

Here is how the fan is wired. I added an 60 amp fuse with 8 gauge wire from the fan to the relay and the relay to the battery..
http://www.chevelles.com/showroom/data/500/dia-1.jpg

i think you will be fine with the 2-gauge from the alt. to the battery.
no need to run a larger wire from the battery to the horn relay unless you have a 3-wire altenator and will also need to run power for the headlight relays to provide more voltage/current to the headlamps for brighter lights. the 3-wire alt. has a sense wire that will sense the voltage at a point you want to monitor such as the horn relay buss-bar, also the 3-wire set-up will allow you to use the gen (idiot) light on the dash. it will come on if you are starting or throw a belt or have low charge conditions.:thumbsup:

The horn relay is the main power distribution. I would run the alternator output to it. Also I would connect the power feed for the fan relay to the horn relay not the battery.

i think you will be fine with the 2-gauge from the alt. to the battery.
no need to run a larger wire from the battery to the horn relay unless you have a 3-wire altenator

The horn relay is the main power distribution. I would run the alternator output to it. Also I would connect the power feed for the fan relay to the horn relay not the battery.

You definitely need a larger wire from the alternator to the power distribution point. The wire from the alternator to the battery doesn't need to be very large, as the battery only needs recharging current.

Also upgrade the chassis grd wire, battery to passenger side front fender. This is the return path to the alt. If only the positive is upgraded you run the risk of burning up the chassis grd wire.

Thanks for the help guys, I just have a mental block with wiring... This project could be beyond my knowledge, I guess I will just have to start tearing stuff apart and find out where it goes.

Does the main alternator power wire go to a splice before going to the horn relay??

I think I understand that the main wire will need to be upgraded to the horn relay(2 gauge), but no need to upgrade from the wire from the horn relay to the battery, is this correct??

Sorry if I am repeating myself, I just have trouble visualizing this type of stuff. I never understood Algebra until someone showed me step by step what to do, so thanks for your patience...

I've got a CS-130 alternator in my '69. I put in dual 8 ga wires from the alt. to the distribution point. You don't need a system to handle 140 A. You should size the wire for the load required. You will normally only be using a fraction of that current. If you are actually going to be continuously drawing 140 A then you need an even bigger alternator.

I've got a CS-130 alternator in my '69. I put in dual 8 ga wires from the alt. to the distribution point. You don't need a system to handle 140 A. You should size the wire for the load required. You will normally only be using a fraction of that current. If you are actually going to be drawing 140 A then you need an even bigger alternator.

I am thinking of going to the 140 because the 100 amper I have now is only showing 13.20-13.60 volts when the fan is running and the car is idling. Is that enough volts to keep the battery charged? The system is on my bracket racing car and the last thing I want is to have a dead battery in the staging lanes...

Also can an external regulator handle the current load from my 100 amp alternator??

Thanks guys, TC ROCKS!!!!!!!!!!!

I am thinking of going to the 140 because the 100 amper I have now is only showing 13.20-13.60 volts when the fan is running and the car is idling. Is that enough volts to keep the battery charged? :yes:that should be enough to keep it charged, you should figure out about how many amps the car is actually using before making changes and buying a large amp alt.
The system is on my bracket racing car and the last thing I want is to have a dead battery in the staging lanes...

Also can an external regulator handle the current load from my 100 amp alternator??:noway:stock type external regulators are only rated to handle about 62-amps, you must not be pulling that many amps or you would have had problems already........

Thanks guys, TC ROCKS!!!!!!!!!!!
:thumbsup:see above responses also the stock alt wire (red 10-gauge) goes to a splice on the harness and splits off to the horn relay and to the fuse box on the firewall. the alt. will only produce up to the amps rating when the load is large enough, meaning a 100-amp alt. may only put out 45-amps at idle and when engine rpms go up it will rise to the max draw of you car. that's why you should figure out total amps needed (lights. ign-box, fan, radio, gauges, fuel pump, etc.) hope this helps.......:thumbsup:

Thanks Vince......

I am thinking of going to the 140 because the 100 amper I have now is only showing 13.20-13.60 volts when the fan is running and the car is idling.

Where are you taking that voltage measurement at? The only place thats important is at the battery. Any readings from the fuse box will be lower because of voltage drop.

Where are you taking that voltage measurement at? The only place thats important is at the battery. Any readings from the fuse box will be lower because of voltage drop.

I am taking the voltage reading directly at the battery posts...

I need some help, I moved the power wire for the fan relay from the battery to the horn relay. At idle when i check the volts at the battery I now have 14.30-14.40, steady, instead of 13.30-13.60 when it was connected to the battery.

The car will not start after I let is run a while or go around the block a couple of times. I always check the voltage and even when I pull in the garage after a ride, it still shows 14.30-14.40 at the battery at idle. When I turn the car off I still have 12.50-12.60 at the battery.

Could the battery just be too weak to begin with, it only has 600 something cranking amps??

Why is the battery not charging, do I just need to give up on my old set up, and convert to an internally regulated CS130 type alternator, and run the 8 gauge wire, ect, ect??
THanks...

The higher voltage at the battery is because you're not drawing as much current through the wire from the horn relay to battery. That was causing a voltage drop, lower voltage at the battery. You've got a reasonable charge voltage at the bat now, over 14v, and a good charge on the battery, over 12v. You don't need a new alt to solve you're starting problem.

You might have the common heat soak problem. The starter heats up from engine heat and won't start until it's cooled down. Make certain the connections on the starter are good and tight and clean. Also the connections at the battery and main ground wire to engine. May not solve the problem but it's a start. Any corrosion of the cables at the ends and they should be replaced. Do a search of this forum for 'heat soak', should come up with lot's of reading material if you want to know more.

The higher voltage at the battery is because you're not drawing as much current through the wire from the horn relay to battery. That was causing a voltage drop, lower voltage at the battery. You've got a reasonable charge voltage at the bat now, over 14v, and a good charge on the battery, over 12v. You don't need a new alt to solve you're starting problem.

You might have the common heat soak problem. The starter heats up from engine heat and won't start until it's cooled down. Make certain the connections on the starter are good and tight and clean. Also the connections at the battery and main ground wire to engine. May not solve the problem but it's a start. Any corrosion of the cables at the ends and they should be replaced. Do a search of this forum for 'heat soak', should come up with lot's of reading material if you want to know more.

Thanks for the response Hank. I was thinking about heat soak, but the thing is I had ran the car for about 3 years with no problems, until I added the fan, but I will for sure check the grounds and connections. BRIAN....

Thanks for the response Hank. I was thinking about heat soak, but the thing is I had ran the car for about 3 years with no problems, until I added the fan, but I will for sure check the grounds and connections. BRIAN....

Check the battery to starter connection and the connection on the 'S' terminal of the starter as well. When the fans where hooked to the battery were they hooked directly to the battery or the junction block. Check the connection at the junction block and the horn relay as well. Any bad connection in the positive circuit can drop the voltage going to the starter. When it's hot it requires more current and a bad connection can keep it from starting. A marginal connection, positive or ground, may not show up when the car is running or cold but a hot starter requires a lot of current.

The car will not start after I let is run a while or go around the block a couple of times. I always check the voltage and even when I pull in the garage after a ride, it still shows 14.30-14.40 at the battery at idle. When I turn the car off I still have 12.50-12.60 at the battery.

Recheck the battery connections. If it had always started before, the problem is probably there as it was the last thing that was touched.

When you have the starting problem is fan running? What I mean is the engine is hot, when you turn the key on does the fan run? If so it could be lowering the voltage in the start circuit enough to keep the solenoid from picking up.

When you have the starting problem is fan running? What I mean is the engine is hot, when you turn the key on does the fan run? If so it could be lowering the voltage in the start circuit enough to keep the solenoid from picking up.

No I have a manual switch inside the car, that controls the relay. I always start the car with the fan off and kill the fan a second or two before killing the motor.

Check the battery to starter connection and the connection on the 'S' terminal of the starter as well. When the fans where hooked to the battery were they hooked directly to the battery or the junction block. Check the connection at the junction block and the horn relay as well. Any bad connection in the positive circuit can drop the voltage going to the starter. When it's hot it requires more current and a bad connection can keep it from starting. A marginal connection, positive or ground, may not show up when the car is running or cold but a hot starter requires a lot of current.

Sorry but where is the junction block and whats it's function?? Thanks...

Recheck the battery connections. If it had always started before, the problem is probably there as it was the last thing that was touched.
Will be checking, cleaning, or maybe replacing battery cables, grounds, ect over the enxt couple of days...

Junction block, if it's still there, is mounted on the rad support next to the radiator, almost behind the battery. You should have a smaller wire coming off the positive battery post, it goes to the junction block.

While you're at it. If your battery ground cable is connected to the head or the alternator bracket, move it directly to the engine block. The boss in front of the engine by the fuel pump is a good location. At any rate make sure the bolt threads attaching the cable are clean and put an internal star lock washer before and after the cable lug. The star washers will bite into the metal and help provide a lasting electrical connection. "Heat Soak" start problems are sometimes traced back to "iffy" battery ground connections. Let us know what you find.

While you're at it. If your battery ground cable is connected to the head or the alternator bracket, move it directly to the engine block. The boss in front of the engine by the fuel pump is a good location. At any rate make sure the bolt threads attaching the cable are clean and put an internal star lock washer before and after the cable lug. The star washers will bite into the metal and help provide a lasting electrical connection. "Heat Soak" start problems are sometimes traced back to "iffy" battery ground connections. Let us know what you find.

:):):):)

Ok I figured it out, I think. Connected the main ground for the battery directly to the block, cleaned and repaired all connections and WOW no starting problems. I ran the car for about 30 minutes got it nice and hot, and she started right back up.

Thanks everyone for the all the help.