Hi All:

Just a few pics of an upgrade from a 95 amp old style to a newer style 140 amp alternator.

A few years ago I upgraded installing a bigger electric fan, a MSD Atomic TBI, and an operational air conditioning system. At that time I upgraded to an old style 95 amp alternator to account for more power consumption.

The 95 amp system was always marginal and this summer I noticed the MSD controller showing under 12v. Recently the car failed to start and the AAA rescue tech tested the alternator and showed it was under performing.

Thankfully there are a number of posts here on the forum of how others solved the problem - a CS144 alternator. There is consensus that a larger cable is needed to carry the additional power down to the positive terminal of the starter solenoid. Some say to replace the stock cable with a larger gauge conductor and some say to run a parallel cable and leave the stock cable in operation. I choose to run a parallel second cable.

The new CS144 was readily acquired at the auto parts store along with the pigtail to connect the old connector to the new style alternator. I ordered 6-gage wire and a 10-gage fusible link from Amazon, and picked up terminal ends, copper connectors and shrink wrap from the hardware store (auto parts store did not have terminal ends for 6-guage wire).

The install went fine starting by cutting the additional cable to length, hammering on the terminal ends, jacking up the car and crawling under to attach the additional cable to the solenoid, then chasing it up to the alternator. Next the new alternator was mounted which exposed that the old alternator belt would not work with the new alternator. Another trip to the auto parts store solved that.

Seems to work pretty well. With all systems running while at idle the alternator maintains about 14 volts. Upgrading to the more powerful alternator looks like a pretty good option. A couple of additional points - the cooling fan turns faster at a higher voltage which is helpful and I wonder if the MSD idle air control motor also responds quicker at higher voltages which would make that system run better too.

 

Is the fusible link at the alternator end of the wire? It should be at the starter end to protect against the wire shorting out somewhere along it's length.

 

Any chance you'd have the part number for the larger belt? Also what specific cs144 alternator did you use? Thanks!

 

I have had my CS144 140 amp alternator for about 10 year now with no additional amperage draw accessories with the stock wiring and just this year added an 8 gauge wire that runs from the alternator to the starter in parallel to the stock wiring with an 80 amp fuse right off the alternator to the 8 gauge wire.

I guess am confused about the fusible link closer to the starter than the alternator? I ran my 80 amp fuse along with the 8 gauge wire right off the alternator since any short along the wire to the starter would blow the 80 amp fuse caused by a surge in amperage above the 8 gauge wire which is rated 150 amps at 7 feet but will blow at anything beyond 80 amps. Using the 8 gauge wire with an 80 amp fuse in parallel to the stock wire and fusible links provide loads of protection for a 140 amp alternator. Seems more logical to have the fuse/fusible link closest to the power source just like in a circuit breaker box in your home...any short after the breaker will cause the breaker to trip or fuse to blow.

The beauty of my system is that if the 80 amp fuse blows or shorts due to a wiring issue, the car will run on the stock system like it has for 10 years or if the OEM fusible link blows, the 8 gauge wire will keep the car going with 80 amp reserve. I have a 140 amp alternator not for the amperage rating but for big amp output at idle and faster charging after a battery drain such as a cold start....

 

The battery is the power source you need to be worried about. If the wire shorts, the battery can supply a lot more current than the alternator.

 

I've been intentionally avoiding learning about this although, this upgrade probably needs to be #3 in my queue right now...

I'm going to ask some dumb questions:

1. I thought CS144 alternators all came with serpentine-style belt pulleys- can you buy them with V belt pulleys?

2. You just ran the new thicker wire from the alternator to the starter?

3. Fusable link thing- is the power actually running through the smaller gauge wire to act as a poor-man's fuse? If so, then what the heck is the point of running the 6 awg wire at all?


Adam

 

 

1) You just swap your old pulley over.

2) Basically yes. You will also need an adapter harness from SI to CS style. $10 You can change the end, but I used an adapter so if I break down nowhere land, I can jamb an SI back on easy.

3)It's all about the total resistance of the circuit. That short piece of smaller gauge wire can handle the load. Your just giving it a good place to fail if you have a catastrophic failure. You still need say a #4 to handle the full output.

 

The wire that you need a breaker on is the stock wire. It's the one that was installed with a 63 amp alternator and has the potential to be overloaded by additional accessories. Parallel wiring probably will not offer continued operation in the event of a short on the 8 gauge as it's short may also render the alternator inoperative.

Your 8 gauge wire runs no risk of being overloaded by current draw from accessories used in the car. It's biggest threat is having a short between the starter lug and the alternator and still drawing current from the battery. An essentially unlimited source of amperage. That is why a fuseable link should be used on the starter side. A fuse could conceivably work there, but there is a lot of heat in that area from the exhaust and it may blow prematurely.

 

I agree with "why run #6 or 8 if the fusible link is a #10, 12, or 14 gauge" defeats the purpose. What about these breakers?

 

Fusible links have been used successfully in 100's of millions of cars. They do work. The length is only about 7" so the voltage drop is small. 7' vs 7" of wire makes a big difference on the voltage drop.

I bet you could take 6' of #6 wire off the output stud of the alternator and short the other end to the case and the alternator would die before the wire insulation melted.

 

Hi Everybody...

Appreciate the interest and replies to the post...

Yes, the CS144 did come with a serpentine pully block and I did switch it out for the v-belt version from the old alternator. I believe it was a 15/16's nut and required a light duty electric impact driver to remove and replace.

The alternator was procured from O'Reilly Autoparts and I followed the lead of another post here on the forum and asked for an alternator for a '94 Chevy Impalla SS - which had the mounts at 12 and 6 on the clock. The bottom mount did require a spacer on the bolt and I already had one that was necessary for the old alternator.

The drive belt... it is a Duralast 15545 from AutoZone.

The fusable link near the alternator... the stock fusable link is near the starter. I understand the logic that the link protects against current from the battery. When I catch my breath from other chores I'll turn the cable around so the link is at the starter.

 

GM also used ignition switches in 30 million cars- which resulted in only 124 deaths- way less than .0005%- Percentage wise that sounds successful...

I like fuses-

Like I've said before -short the alternator-the only smoke you'll see is out of the alternator. The battery is a different story.

These old cars-when the electrical system was designed -They no idea that current hogs like electric fans- stereos etc would be added-

A battery fuse might not be a bad idea-










Fusible link-

Article-

http://www.dragzine.com/tech-stories...rancis-wiring/






"Prevent Fires

Many racers and enthusiasts are still in the habit of installing a fusible link, as those are what had previously been provided by the OEM’s for years. Old habits die hard in the performance industry, and fusible links are no longer an accepted way to wire a performance vehicle. “Have you ever seen one of these things light off? There’s a reason why they are not used any more. Consider a Maxi Fuse,” he says.
As seen here, a fusible link is a poor choice when wiring a vehicle. RFW's Scott Bowers suggests Maxi fuses instead to handle larger current loads.

As seen here, a fusible link is a poor choice when wiring a vehicle. RFW’s Scott Bowers suggests Maxi fuses instead to handle larger current loads.

Maxi fuses are fast-acting, blade-style fuses that have been designed to take on larger loads than a regular ATC or ATO-style fuse, and have become the industry standard for vehicle circuit protection. Maxi fuses are commonly rated from 20 to 120 amps."

 

You want this fault protection at the source end, meaning the battery end.

Breakers don't like weather and heat. The starter location is not a good place for them.

You want something that only fails under a large fault.

A fuse should probably be 300% . Lionel could calc. the fault current.

If you do this, you want to use the starter cable as the buss. If an alternator loses connection to the battery, it can surge to 100V. If a load is connected to the alternator directly, and the fuse blows, any load upstream could see 100V, and that would also be catastrophic.

 

1. I did not know that; now I wonder why I've been avoiding this for so long! Thanks!

2. Agreed definitely the way to go.

3. That makes sense; I still can't wrap my head around intentionally burning up a small piece of wire instead of a small fuse or breaker, but I get it now.



Now if you're just removing the old alternator and installing this new one with the original pulley, then why did you need a new belt?




Adam

 

If you planned to install an underdrive crank pulley, do you feel it would be necessary / a good precaution to install an overdrive alternator pulley while doing this swap?


Adam

 

I didn't.
Depends on the diameter of the alternator. A smaller Denso unit would need a shorter belt. Just depends on where the centerlines line up.

 

What does the ignition switch have to do with a fusible link?

GM is not the only company using fusible links.

I've never had a fusible link fail for no reason. I did have a fusible link fail because someone poked it with a test probe and the wire corroded inside the insulation.

On the other had I had the main battery fuse in a Honda fail for no reason.

 

No free ride . Underdrive takes away efficiency. Powermaster shows min-max rpm matching. Look in their cat.

 

People who put a 80A or 100A fuse on the 6 gauge primary power wire to make sure the wire is protected make me smile at how ridiculous that is. As a test I once put about 500A AC through a 5' piece of T90 10 gauge wire until the insulation started to melt. It took over a minute before the insulation started to show any signs of being heat stressed. Wire and insulation is much more durable then most people realize.

So, yes I'd agree that a fuse should be sized much larger than most people expect. For a 6 gauge wire connected a 140A rated alternator I'd probably use a fuse rated around 250A to 300A. The automotive fuse types typically don have much for a time delay characteristic and you don't want a random surge taking out the fuse unnecessarily.