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Hi, Guys. I’d like to replace my 63 amp alternator on my ‘78 Coupe. I can’t seem to find a good vendor to purchase from. The ones on Jegs, Corvette Mods, Ecklers, Amazon, AutoZone are not floating my boat. Any suggestions would be appreciated. An upgrade to 75-100 amps works. Thanks.👍
I used a Powermaster 8002 on my 71 LS5. I had to clock it to get the proper orientation for the ground, power output wire and the plug for the regulator. I chose not to use a single wire setup. I am happy with it.
Thanks. Mine has a 2 wire setup, so I thought it would be easier to replace it with a 2 wire. A Two wire setup seems hard to find. How many amps is yours?
Don't mess around half-assedly. If you are going to get a better alternator then go to a 140-amp CS-144...no need to half-@ss things with some "upgraded" 12si if you're upgrading the alternator. They're readily available and inexpensive and GM.
Take the readings below to determine the status of your wiring to begin with......
Here are some pointers for that: Here is the guidance I used to find the adapter for my CS-144 (been installed since 2007)..... should work for a CS-130 from what I have researched. If nothing else you'll know how to measure resistance. (Additional info: I also had converted my 68 from an externally regulated 10dn(?) to an internally regulated 12si. I bought the 12si-to-CS adapter because when I did it CS-144s were still somewhat rare. Works out good though, I swapped in my old 12si one day when I thought I had messed up my CS-144 and it worked just fine.)
You can do the quick check below to see what adapter you need to convert from 12si to CS-144 ...then go to the local parts store and get the equivalent part. I went to NAPA, mine took Echlin part # ECH EC82 .... according to NAPA website that is part interchange number for 8078 in text below. (Per NAPA website: 8077 cross-references to Echlin part #ECH EC80 8078 cross-references to Echlin part #ECH EC82)
(****THAT WAS FOR MY VEHICLE ---YOU NEED TO DETERMINE YOURS****KEEP READING).
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
...the above text is from idavette dot net (doesn't appear to work anymore).
that's the guidelines I used to wire mine in and it worked from the get-go.
Ok. 120 amp would be fine. Did you add a fuse with the 10 gauge?
You have to realize- when the alternator shorts out- you'll see some smoke and -it quits working.
The battery is a different story- if it shorts out- it KEEPS on putting current out- and only quits when the wire has burned in half-
See the diagrams below- just adding another wire WILL bypass the fusible links- giving you UNPROTECTED full battery power on small gauge wire- not a good combo-
I highly recommend spending $30 or so bucks protecting at the battery-
Ok. Great chart. For $30, it’s well worth the protection. I was concerned about going to a higher amp alternator due to my stock wiring. This solves the problem. My current alternator is not keeping up with my A/C draw. I have to keep the battery tender attached in order to start the coupe...
Dutch647
I got a 140-amp Cs-144 for 22 bucks at a boneyard 13 years ago. Still running. It cost me more for the adapter plug and the belt (35 bucks) than for the alternator.... and CS-144s are even more common now.
I only picked it up to see if it would fit on my bracket and it turned out to be good....so it is still going.
And YES they are well worth the upgrade. They work a lot better at idle and are just an all around much better alternator.
Originally Posted by Dutch647
Great no. The CS-144 are about 2x the price of the 150 amp models. Are they worth the extra $$$.
My alt is a 17si 108 amp factory rated.....larger diameter, I set it up for serp drive....been on there over 20 years.....stock wiring, the rad fans and HVAC blower have their own wires/fuses coming from the alt out stud.....
The fuse is intended to "sacrifice" BEFORE the wire melts.
Size of the wire determines the fuse size- that's it. You can go smaller- more protection - but going larger than the wire's rating lends to the possibility of a fire.
So say you are running a 6GA wire- you'd fuse it for 80A- any higher you risk the possibility of fire... Just sayin
C3 Alternator Upgrade
