71roadster

I am going to upgrade my alternator to more current and don't know if it is internal or external radiator. Does anyone know or know how to tell?

I need to run electric fans and power windows and a fat stereo and am wondering how high a current alternator to run. Anyone have any ideas?

Is there anything else in the electrical system that should be serviced while I am at it?

kits are available here... http://www.alternatorparts.com/

Thanks
Chris

Larry B.

All corvette from '69 have internal regulators so you can use a later model alternator. Be aware also that due to Corvettes having SMALLER diameter crank pulleys, they use corvette specific alternators that produce higher voltage at lower speeds. Parts places often call out for a "Chevy" unit. This will work fine at speeds above 1100rpm but not so good at idle. A common problem with generic parts.

mrvette

Use the large 108 factory amp rating, it's slightly larger in diameter, can be hooked up into a one wire system by a local rebuild shop who knows what he's doing.....and it works fine....it's from a Caddy seville with rear window defogger option....say '79 or so....
never attempt one of the newest style alternators, they are junk, totally unreliable...

GENE

zwede

Gene's advice is good. For my '71 I went a slightly different route. I have BIG electric fans (25A) plus a big stereo. I got a 12SI alternator from a 81 Corvette. It's only rated at 80A, but it cranks out most of this at idle. The older 10SI are rated upto 63A, but produce very little juice at idle. I have tested it with stereo on, fans on, headlights plus wipers and the amp gauge sat at zero at idle (no battery drain).

The only modifcation in making the 12SI fit was to bend the bracket slightly as the 12SI is 6" diameter where the 10SI is 5.5. I re-used the stock Corvette specific pulley.

mrvette

Markus, I highly recommend the 17SI series for the newer cars also...
some 2 years ago or so, Hib Halverson and I went round and round over this issue, me taking the side that GM screwed up and all the CS series alternators need replacing with the SI series from older cars....
mostly the older ones can be made to fit well with few modifications and certainly will cost less, and be infinately more reliable...so IF one wants to keep their car...it's a worthwhile change.....

so for a C4 it's fine.....now I run my '72 with electric fans DPFI, and 700r4 and such plus mucho grande' electronic poopie without any problems, using the 17SI series alternator....108 amp rating...sometimes maybe that rating can be upped by certain rebuilders....but I"d need a load check confirming that to believe it....the stator is would with just so much wire/thickness/length that and the diode rating determines the output...the input to the rotor section being of less importance and of course the larger case allows superior cooling, regaurdless of field gap...

GENE