Okay, a little background. The CS130 is known for getting hot and burning up when under heavy loads because of over heating. I knew this was an issue, and always assumed bud air flow.

I am in the process of re-casing my CS130s with new chrome cases. The alts are new and the cases are new so I wanted to practice with an old dummy CS130 that was not any good.

I took this CS130 apart as a dry run for the upcoming chrome rebuilds. What I found a black disc, covering almost everything that gets hot. There is a small hole int eh center of this disc that the air is supposed to flow through, and over the heat sink.

I spoke with a man that rebuilds these alternators for a living and discovered that he discards them when rebuilding. They serve no function that he can determine. In his experience...with out the disc the alternator runs a lot cooler and he has never had a rebuilt one come back burned up.

I would say, judging from these pics I took that he's right, and without the discs more air can flow. You can see on the bottom there is heat transfer compound similar to what's found on a computer's CPU under the heat sink.

That tells me that the entire unit gets hot...not just the fins that are exposed by the small hole. By leaving out the disc I will in effect be letting more air pass through the case and more of it will pass directly over the hot components.

This info could be useful to anyone with a CS130 installed in any of their cars...like your Corvette. They are easy to disassemble and taking out that disk does not require a full tear down.

With disc.


Without disc.


Back of Regulator, Rectifier, Brush Rack. (Note white heat transfer compound.)

 

Why not just get the CS144

 

Well, in my case I want two alts that don't ever have to work at full capacity. If I went with a 144 it would get worked hard. Also, I like the way the 130 looks over the 144, and they are easier to mount in places that were designed for an SI.

Also, I can buy a BRAND NEW CS130 for $70 shipped. A CS144 costs more than twice that.

 

Ahh, this is actually one that I know. The disc is there to concentrate the airflow over the cooling fins on the hea sink. Not saying it works out that way, but thats what its there for. Your right about the whole thing getting hot, it certainly does and the thermo conductive grese you found in there is there to give the heat sink a good thermal connection to the case. The thought is that concentrating the airflow to the fins will cool them faster and thereby conduct the heat away from the other components better than by air flowing over the whole thing. Wouldn't have been my choice to go that way, but then again the General didn't ask.
Removing the disk will probably work better than with it in there.

 

Yeah, I understand why they did it this way...but it just seems like they outsmarted themselves. I want to do some temp tests when I have multiple alts working, but that won't be for a few months.

 

I stuck with a 108 amp large diameter 17SI series alt...like came on defrost rear window Caddys....'79 Seville.....

parts are cheep....

just chang the pulley around, mounts like any otner 12 oclock alt....