1981 alternator questions
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From: Farmington Connecticut
1981 alternator questions
I'm going to replace what I think is a 63 amp remanufactured alternator with a 70 amp. My car has the rear defogger so I'm not sure why the PO installed the 63 amp. (Might explain why the defogger fuse was missing.) The 63 amp alt is so close to the valve cover that I can't fully pull the plug out which makes me suspicious. The 70 amp alt is clearly bigger so I'm expecting problems. Are the mounting brackets for the 63 and 70 amp alt different? Is there a longer v belt required for the 70 amp? I'm nervous that the pulleys won't line up and the current belt is too short. Everything under the hood is stock including all the emissions and A/C.
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The mounting bracket should work with all 10si alternators. My 80 runs a 150 Amp 12si Powermaster alternator, and should be the same aluminum bracket that you have. If you plan on electric cooling fans or other accessories in the future, consider an aftermarket 3-wire alternator. I think CS-130 alternators will also work with the appropriate V-groove pulley.
Belts are cheap. I bought several Gates belts at RockAuto on closeout for $1- each, and used whatever fit.
A Corvette alternator should be "clocked", to have the two-wire connector at the top, away from the valve cover. There are instructions on this Forum.
Please post a photo!
Belts are cheap. I bought several Gates belts at RockAuto on closeout for $1- each, and used whatever fit.
A Corvette alternator should be "clocked", to have the two-wire connector at the top, away from the valve cover. There are instructions on this Forum.
Please post a photo!
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From: Farmington Connecticut
I installed the 70 amp alternator. (NAPA rebuild) Both brackets fit and the pulley lined up as it should. The plug on the 70amp is at the 6 o'clock position so that problem went away. I needed to get a longer belt and found a NAPA PBH 15550 that works so far.
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St. Jude Donor '22
hot bat feed 6 oclock and the 2 ground wires
3 oclock. hoses loop bolts over ground wires
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From: Farmington Connecticut
Anyone know if the front half and back half of the casing can be spun 180 degrees to each other? I would rather have the two wire plug opposite the exhaust manifold like interpon's picture. Thanks.
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From: Indiana
http://www.madelectrical.com/electri...elcoremy.shtml
a few vids as well..its easy..also iwould move that fround off case cover bolt
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St. Jude Donor '22
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Disconnect Battery.
Disconnect all wiring at alternator.
Remove belt
Remove the (4) hex head screws from alternator, Don't let alternator separate to much, a little is OK...or your brushes will fall out.
Try to KEEP alternator flush against the mating surfaces.
Your "center" or STATOR will rotate with rear case.
Rotate rear half of casing so electrical connections are like interpons.
Re-insert hex head screws and tighten evenly.
Test pulley rotation that it is smooth and free.
That is clocking.
Disconnect all wiring at alternator.
Remove belt
Remove the (4) hex head screws from alternator, Don't let alternator separate to much, a little is OK...or your brushes will fall out.
Try to KEEP alternator flush against the mating surfaces.
Your "center" or STATOR will rotate with rear case.
Rotate rear half of casing so electrical connections are like interpons.
Re-insert hex head screws and tighten evenly.
Test pulley rotation that it is smooth and free.
That is clocking.
Last edited by bmotojoe; Oct 30, 2021 at 09:33 AM.
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From: Southern Cal Ca
St. Jude Donor '22
unless you remove pulley
the risk of screwing brushes increases.
only move the pulley side of case keeping
the armature firmly in place.
an allen wrench and 15/16 boxed to remove pulley.
clock it how you want, apparently.
the risk of screwing brushes increases.
only move the pulley side of case keeping
the armature firmly in place.
an allen wrench and 15/16 boxed to remove pulley.
clock it how you want, apparently.