Alternator Swap Into 1970 S2 65/2400  


This swap was performed in 1985 when the original French SEV Motorola alternator died.  I wanted to source a US alternator and solid state regulator for ease of future rebuild and/or replacement as well as get extra capacity.  

The Alternator   

I went to a local rebuilder here in the Washington, DC area in 1985 and essentially said "who put Motorola alternators in their cars?" so I did not look it up by application, but they told me it was for a 1971 AMC Javelin.  At least that's the wiring diagram I photocopied.  I have checked various web parts stores and they all have a listing for that car with a Motorola alternator of 55 amps.  A recent search of shows current listings for the 1971 Javelin application with a 55 amp Motorola unit with a part designation of 7429.  Some of the 7429 units listed show up as Delco units while the others are Motorola.  

The Voltage Regulator    

The regulator I have is by Guaranteed Parts Company of Seneca Falls, NY.  P/N VR291.  They are now GP Sorensen, a subsidiary of Standard Parts Co. and the part number is the same and is also listed for the Javelin application on  I'm sure you could cross reference the number at any quality parts store.  

The Connections   

The regulator has four leads into a connector: Orange, Green, Black and Yellow.  Black and Green go to the field terminals.  Orange goes to a tap off the diode bridge used to sense voltage.  Yellow goes to switched voltage.  That's it.  If you need a wiring diagram, find one in a Motor's manual or similar or contact me and I can try to help.  


Here is where having an American Motorola alternator is useful.  They have essentially the same case except for the tension adjustment bolt mounting hole.  You need to perform a little surgery and a little creative fabrication.  Remove the stamped sheet metal bracket from the back of your original alternator (the one that makes up the back half of the mounting through which passes the main mounting bolt to the cast bracket on the head) and install it on the new alternator.  You may or may not have to use the long case assembly screws from the old alternator (I just don't remember) to accommodate the extra thickness of the stamped sheet metal bracket.  There are two ways to accommodate the different mounting point for the adjuster arm.  The first way I did it was not the easiest way overall, but was easiest for me when I had a sheet metal shop at my disposal: I made a simple sheet metal bracket (I used 16 gauge steel) that completes a half circle along the top of the alternator between the main mounting bolt and the tapped adjuster bolt hole.  Drill a hole in the bracket at a point which allows you to attach to and use the stock adjuster bracket to set belt tension.  The first two of the attached pictures show the front and rear of this installation.  Also attached is a dimensioned drawing of the adapter bracket. 

Since then I have discovered an easier way: buy a new adjuster arm!  I found a “universal alternator/generator adjuster arm” in both the Summit Racing and Jegs catalogs (Jegs was a little cheaper).  Jegs part number 778-66115 was $9.99, now $7.99.  This arm has to be slightly modified by cutting off the first mounting hole (of two) on one end and replacing the existing adjuster arm;  a much simpler, cleaner and sounder installation.  It’s also chrome and looks better.  The third picture shows the newer installation. The fourth picture shows the adjuster arm itself  

It is installed on an 807-13 crossflow motor, but all mountings are identical to, and will work with, the stock engine (I had mounted the original alternator when I did the engine swap).   

Your mileage may vary!   

Good luck, I hope this helps.  If you have any other questions let me know.  Let me know of any problems or improvements to the scheme at   


Guy Arnos 

 1970 S2  



Alternator Front  


Alternator Rear (note stamped metal bracket) 



Alternator Front with New Universal Adjuster Arm


Universal Adjuster Arm (Part C)