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Retrofitting a Delco 10si Alternator
The alternator finally quit working on my
American. Instead of spending the money on a stock replacement (40 amp
Motorola), I went ahead and replaced it with a Delco 10si (65 amp). This procedure should
be the same for any AMC 199/232/258 equipped with a Motorola alternator.
You'll need to buy the following items to do this
1 - Delco 10si alternator. They should be able to just yank
one off the shelf, but if they insist on knowing what its for, pick your (least) favorite
72 to 87 rear drive GM and ask for one for that.
1 - GM style alternator pig-tail.
1 - Post type crimp connector. Get the blue ones with a medium size hole.
Solder, wire strippers, wire cutters, shrink tape/tube, wire ties, soldering iron/gun,
miscellaneous sockets and wrenches.
NOTE: You will need to machine the alternator's pivot boss to allow it to
fit into the factory brackets. Keep in mind that when you do this, you void any warranty
the new alternator has.
Begin by disconnecting the battery and removing the old alternator.
Measure the length of the pivot boss on the old alternator and cut the pivot boss on the
new alternator to this length. It is very important that you do not allow any metal
shavings to get into the alternator. If you wish, you can remove the front of of the
housing by removing the pulley and the 4 through bolts. Once the boss is cut to length,
remove the 4 through bolts from the alternator and rotate the case 90 degrees so the
wiring plug on the side is opposite the pivot boss. Reinstall the through bolts.
Once that is done, you'll need to make the following changes to the vehicle wiring (don't
worry, you only need to cut one wire!): Remove the voltage regulator and cover the open
connector with electrical tape. Cut the connector off of the field + wire (cut it back far
enough so you can reattach it later if you want to convert back to the Motorola style
alternator) going to the old alternator. On my car, it was orange. Check the wiring
diagram for you car to make sure. What you are looking for is the wire that comes from the
warning light on the dash. Solder this wire to the white wire on the pig tail. Crimp a
post style connector on the red wire and connect it to the battery lug. Plug the pig tail
into the alternator. Connect the original battery output wire to the battery lug on the
Install the new alternator. You'll need to move the upper alternator bracket slightly
since the Delco alternator is slightly taller. Install the belt and tighten to specs. Cover
the left over connectors with electrical tape to prevent shorts and then wire tie them out
of the way. Voila! You're done!
August 4th, 2004 Update - I took my American to the "AMC's In The Park"
show in Kenosha, WI this past weekend and the bearings in my rebuilt Delco
gave out along the way. Luckily, Kennedy American (614-879-7283) was
there selling Power Master brand Delco style alternators that were already
machined to drop into the Motorola brackets (I picked up a 100 amp unit). I did run into one problem with
these alternators and that is that they are slightly wider than a Delco 10si
and hit the power steering gear before the belt is fully tight. The solution
was a half inch shorter belt (36 inches overall). I used Dayco belt #15360. If you have standard
steering, the stock belt (Dayco #15365) should work fine.
08/04/04 10:43:19 PM