Alternator upgrade. Which is best

[71rehab]

I suspect I have a bum alternator. I'll test it tomorrow after I've fully charged the battery but today, on a full battery, the truck started 4-5 times before not having enough juice to turn the engine again.

IF it is bad, and I need a replacement, does anyone have a recommendation for a '71 C20?





71 C20 CST

[starterman99]

If your battery went low after only 5 starts I would also have the battery load tested.

[71rehab]

Good call. Also noticing that the battery that the PO put in it is only 600CCA.

[toiletbowl54]

Go to a web site called Mad Electrical. It has a lot of info. on alternator upgrade, I assume your's being a 1971, it has an external voltage regulator. You might consider installing a alternator with an internal voltage regulator.

[Dead Parrot]

600CCA should be plenty for a stock motor on a not below freezing day. Don't rule the battery out as the problem. Even new batteries can fail. Why they have warranties.

Double check the battery cables. They may be EOL even if the outside looks fine. The battery acid can rot them from the inside.

Unless you have a show quality truck, 2nd the suggestion to swap to a newer type alternator if your existing one is bad. http://www.madelectrical.com/electri...elcoremy.shtml

[vince1]

I go with the CS130 (Rockauto 89 Pontiac Safari) because it charges better at low RPM's than the old 10si. It may need a resistor to supplement the one in the lamp or if there is no lamp at all so know what you are doing when wiring it up. Newer ones have serpentine pulleys but they can be swapped.

A lot of people like the Powermaster replacements and they may be easier to wire.

Go back through the electrical postings here as lots of the questions regarding upgrades are answered and you will also find the wiring diagrams on how to do it.

[VetteVet]

Here' s a good thread for you. If you go for the CS get the CS 144

http://67-72chevytrucks.com/vboard/s...d.php?t=417872

[71rehab]

Originally Posted by toiletbowl54

Go to a web site called Mad Electrical. It has a lot of info. on alternator upgrade, I assume your's being a 1971, it has an external voltage regulator. You might consider installing a alternator with an internal voltage regulator.

Wow. Really got educated at Mad Electrical. Good site. Thanks for the heads up.