Terminator "Alternator 101"

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  1. #1

    Default Terminator "Alternator 101"

    After doing a ton of research a while back as my OEM 21,000 mile alternator started going down the tubes, I figured there were some things about our alternators worth sharing. Much of this information is taken from the Electrical page of my own site, but it was just as easy to re-post and link it here.

    I'll also skip most of the basics on how alternators work (converting AC power to DC via the rectifier), but there is plenty out there on the internet if you want more information. One document that I found that is fairly informative, entitled Understanding the Alternator, is a nice read though, especially since it explains the internal functions in detail and also differentiates between the stator windings. Definitely a good read! Otherwise, this picture is a good start:

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    In a nutshell, the unique 6G, or Sixth Generation, OEM Terminator alternator is rated at 105A (sometimes listed as 110A). IT'S NOT 130A. Even worse, it's basically just the V-6 alternator with an 8-rib pulley and a different battery cable post on the back...

    Since I ultimately had a local rebuilder upgrade my original to 160A, he not only showed me a bunch of information in his computer system where his parts come from (again, not 130A stuff), he also put two other Terminator alternators on his bench to confirm their output. One was another OEM take-off that I acquired afterwards, with 20,000 miles, and the other is a brand new Ford "reman". The first put out just over 110A and the "new" one, getting spun ridiculously high, was barely able to hit 120A, sometimes a hair over (and they both got nice and warm). Not being an expert on the subject, I believe what the shop owner stated about how a true 130A alternator would have been able to hit levels higher than 130. I guess they are rated conservatively. What's even more unusual, is the spare has a label on the case with "135A" printed on it, but it definitely did not deliver:

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    Taking a step back, Ford is the only place that listed, and still lists, these alternators at 130A - as did FRPP not too long ago - but I think that is information that just slipped through the cracks back in 2002 and gets taken as gospel and repeated. The Order Guide does show a "Heavy duty" alternator, but I think that was what Ford intended, rather than what they delivered. It is not listed as "New For This Model Year", rather as the same information that most likely carried over from the '01 Cobra.

    Apparently, there are plenty of guys that are aware of the lower output rating, but some still insist otherwise (I initially though they were 130A as well, until the research set in). The alternator we got is considered a "small case" unit, that definitely is not of the "high output" variety. The way to tell one from another easily:

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    With that in mind, here is a pic from the brochures and the Press Kit that I'm guessing is a pre-production engine with a "large case" 4G alternator on a mount that is definitely different:

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    Compare this to a production engine with the small case 6G alternator which doesn't jut out as much (a good thing since there is only about an inch between the case and the frame rail):

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    As it stands, I had to dig more after searching through a bunch of vendor sites (RockAuto, CarQuest, Advance Auto, AutoZone, etc.) and coming up with nothing but 105A alternators. Since having mine rebuilt, and then having the shop show me how really easy it is, I decided to start looking around at vendors that sell parts for the DIY types that would tackle this on their own. One place with some great information (including many Ford engineering numbers to cross reference) is Alternator & Starter Parts Wholesale. Here is a screen shot from a search under "2003 Mustang" on their site:

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    Once you are there and click the line for the Terminator (or any other), it opens up a list of all the components with many of the Ford engineering numbers. Just for the heck of it, I took those pages that I also found in another catalog and put them in a PDF document with everything Terminator-specific circled: all listing 110A - and mostly shared with the '01-'04 V-6 alternator. Here is also a GENERIC picture of those parts that can be pulled from the above site:

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    The screen shot up above also references a "Lester 8304" alternator, and if you also want to search under the engineering number info on the rear bearing cap ("FN 2R3V-BA") a bunch more listings also come up showing only 105A replacements. Here are a few more examples:




    Something else interesting when mine was undergoing its transformation: mine worked perfectly with a 2-1/8" pulley to replace the original 2-1/2". Forum lore suggests that the OEM alternators are "over spun", but the owner of the shop assured me that he's never seen high RPM's kill them (well, unless the bearings are shot), rather it is the heat that wipes out the diodes in conjunction with plenty of abuse. For now, the small pulley on mine is doing the trick, and since I have the stock crank pulley and don't intend to race, I figure I'll be fine by not regularly spinning the hell out of it. Here's the "new" one:

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    Anyway, I know that plenty of guys dive in and upgrade to something from Mechman, Nations, etc., but I also wanted to point out how easy it is to not only acquire parts for these, but to rebuild one yourself (again, with NEW parts). They can also be had from local chain stores, and in a pinch, the V-6 alternator is easier to acquire - just don't forget to change the pulley and the post. Thanks to YouTube, another vendor even has a video that shows the re-build process and how straightforward it is if you take that route. Since there are no more new alternators available directly from Ford, this isn't a bad way to go:


    I hope this information proves to be useful.
    Last edited by jrgoffin; 07-17-2017 at 12:08 PM. Reason: Fixed broken pic link

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  3. #2


    i really wish that there was a 3g alternator that would fit the 4 valves, they were the most trouble free, solid outputting alternator i have seen. although the early mark8 had them they don't fit with any other intake. some of the early 3.0 Taurus alternators look like they may fit the s/c 4.6 if reclocked but they are a bitch to pull apart. the 4 g had an annoyingly stupid mind of its own.

    back when i used to run demo derbys i would save the Taurus fans and alternators if they survied, i replaced many 1 and 2gs with them on my vehicles only one failure so far

  4. #3
    Senior Member Array cobraracer46's Avatar
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    May 2006
    Blue state


    As always jrgoffin, your tech posts are outstanding and a huge help for us mustang guys that like to service own vehicles with the best info possible. One the subject of 4 valve Cobra alternators, it looks like the 96-01 Cobra and 2003-2004 Mach 1 alternators are significantly more reliable than the terminator versions. As an example, my 2001 Cobra has 96,000 miles on it and the alternator has been trouble free.

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  6. #4


    Glad to contribute! It is too bad that the Terminator got what amounts to be the V-6 alternator, but the previous 3G and even the Mach1 and earlier Cobra alternators sure seemed to be more reliable.

    On that note, it does appear that one can still buy NEW alternators for the V-6 through Bosch (AL7598N) or even ACDelco (335-1143), and just by swapping out the pulley and the battery cable post on the back, you essentially have a Terminator alternator. For guys that don't want the remanufactured versions, that could be a decent way to go!
    Last edited by jrgoffin; 09-03-2015 at 11:10 AM.

  7. #5


    Very impressive job there Joe! Lots of research and excellent information for the DIY crowd around here. This is TToC material

    Thanks for all the Sherlock Holmes work.


    p.s. Great pics and graphics!
    Last edited by eschaider; 09-03-2015 at 01:29 AM.

  8. #6


    Thanks Ed, it's been interesting to compile some of this. I really wish I would have known about all the V-6 alternator internal parts being the same - would have been a lot easier to acquire one when my original started giving up. Even better, guys that are picky can get them new much easier. The Bosch alternator I listed a couple posts back can be found on Amazon for about $150 - not bad for a 100% new product. May even pick one of those up to check out, but I'm quite confident that a pulley and battery cable post swap is all that is necessary.

  9. #7


    i don't have a terminator to compare to but this looks like the same mounting in a 3g $100 rock auto. it is the alternator i mentioned earlier

  10. #8


    The 3G alternators were nice (upgraded to one in my last Fox Mustang), but the case is larger than the 6G in the Terminator. Adding to that, there are a handful of other variables that probably make it an impossibility to mount in our cars. Definitely a bummer!
    Last edited by jrgoffin; 09-20-2015 at 11:20 PM.

  11. #9
    Senior Member Array P49Y-CY's Avatar
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    Jun 2005


    that's great solid info. reading around the boards there are still a lot of guys who just don't seem to want to let go of "our cars come with 130a alternators!"

  12. #10


    The research was interesting, especially getting time on the bench at the shop. Taking it a step further, I opened up an OEM alternator and the Motorcraft "130A" replacement to compare them - no difference. Hopefully the "our cars come with 130a alternators" crowd will be open minded to all this!

  13. #11
    Senior Member Array Screamn03's Avatar
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    Oct 2003
    Vacaville, CA


    My 70K mile stock alternator just died, weird I read this thread the night before and then the next day it crapped out. I'm lucky it made it back to the house though, pulled in the driveway at 8.68volts, idled fine but couldn't load the motor much or it would sputter (BXT-59 FTW).

    After debating what to do I'm going to give the New V6 335-1143 AC Delco a shot, $150 off Amazon. Will report back in a week or so how it turns out.

  14. #12


    Definitely get some pics and keep everyone posted on the transformation. With any luck, the new alternators will have a much better service life than the remanufactured gear.

  15. #13
    Senior Member Array Screamn03's Avatar
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    Oct 2003
    Vacaville, CA


    Just installed the new V6 335-1143 AC Delco Alternator. Had to swap the pulley and post. Other than that everything else looked the same. The difference in the pulley is obvious, 6 vs 8 rib. The only difference with the post is that the locating lugs on the plastic that keep the + cable from rotating are clocked 90* differently. The post is identical otherwise, same length and clocked the same in relation to the alternator. I thought about trying the V6 post but figured it would strain the cable but in a pinch I think it could work for a road side repair if you happen to break the old post taking it apart. Grinding the two lugs off is another emergency option.

    It's 108* outside, 14.2v idling at 800rpm with no fan, A/C, headlights, or stereo. 13.4v with A/C, low speed fan, headlights, and stereo turned up loud at 900rpm fully warmed up for five minutes. This is driven with stock lower crank pulley and stock alternator pulley.

    Now to see how long it will last. I just needed something to keep the car in running condition for now. Really wanted to do the Mechman but not in the budget right now. I've only put 2K on the car in the last three years so I might not be the best in testing it for durability. Car currently has a 5 year old Motorcraft BXT59 that has always been on a tender but will sink to 12.4v after sitting for a week off the tender.
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  16. #14


    Awesome. Glad it worked out - just don't tell anyone you have a GM part in your car! Hopefully the new alternators last much longer and will be a great alternative.

  17. #15
    Senior Member Array MalcolmV8's Avatar
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    Apr 2012
    Kansas City


    Heat destroys the alternators on our cars. They sit right next to the exhaust manifold. Build yourself a heat shield out of some sheet metal and bolt it up between the two to cut the radiant heat down.
    After a drive grab an IR temp gun and shoot the back of the alternator every few minutes and watch how hot it gets sitting there as the exhaust radiates heat onto the alternator like the surface of the sun lol. You'll be surprised how hot it gets.

    Way back in the day I went the expensive route and got a start-n-charge 160 amp unit. When I had it tested at a local alternator shop it put out closer to 190 amps so it was a beast for sure. I'd get low voltage dips at WOT though. Eventually sent it back. Jamie (owner) discovered a machining issue with the diodes and has since corrected the issue so it could still be an option for anyone interested.

    Myself I decided since heat was killing these things to get a lifetime warranty alternator from my local Advance Auto parts. Some knock that and say who cares if it has a lifetime warranty because they don't want to be swapping them out all the time. That may be true but mine's been going over 2+ years and when it does fail I know I can just run down the road and grab a replacement immediately and be back on the road.

    Just my opinion but I believe no matter how expensive a unit you get its going to fail eventually unless you do something about the heat.

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