Alternator Replacement Options

[FordPrefect]

Tach seems fine. Plugs don't look good, points gap was gone. Set the points, needs timing adjusted. Good spark. Starts, runs for a while then quits. Might replace the plugs but I can't see why it would start but then quit if its the plugs. Kind of at a loss.

[v6spider]

Gm 10si alternator 110 amp with internal regulator. They make a one wire version (goes to bat). All you'd have to do is fabricate a bracket. Most reliable alternator around IMO.

Rob

[70spider]

FordPerfect did you solve your isuue? I hope you did.
I also will have to take the plunge into the mysterious world of alternators, mine works only when it's a full moon . I am cash strpped at the moment so getting a 95amp unit is out of the question. I have been doing some research and found "according to the experts" the stay away from "refurbished" and "rebuilt" ones and get a "remanufactured". With that said anyone out there have any luck with a particular brand? I want to upgrade to a 65amp bosch or at least a 55amp unit. I found what seems like a good from BBB in my price range ($100), there were some good reviews on it, anyone else use this brand?
Thanks

[autotransgression]

no regrets on getting a 95a from allison. it was the tiniest bit finicky to get in, but well worth the effort.

[Exit98]

70 Spider,

Higher amp alts don't make the car run better. The stock alt is more than sufficient for our cars unless you are running aux lighting or other big draw items. There's still an old time starter/generator rebuild shop around my neck of the woods and he rebuilt mine for 75 bucks or so. Plus there are plenty originals floating around if can find one in your area. Nothing wrong with upgrading if that tickles your fancy, but a stock rebuilt unit is a simple R & R and off you go. They you don't have to worry about figuring out the wiring to accomodate the built in regulator and so forth.

Keep it simple I say.

[vandor]

> Higher amp alts don't make the car run better.

As it's been said many times, the main reason to upgrade is not because of the higher available amperage, but because the 95A unit provides about one more volt under similar conditions, making the electrical devices work better.

[So Cal Mark]

"they don't make the car run better". No, not unless you don't have sufficient voltage to your ignition system. And, the high amp alternators make it much more enjoyable to drive at night. Figuring out the wiring is not difficult, the new alternators are the single wire type, and instructions are included

[spider2081]

I have a 10 year old rebuilt 65 amp Bosch alternator on my 81 Spider. The headlights are SYLVANIA H6024 XtraVision Halogen Headlight, the radio is 3 years old. The battery is 2 years old purchased at Advanced Auto but I forget the battery capacity. I measured the alternator output current and voltage while driving the car with everything turned on. The voltage never dropped below 13.5 volts at idle and the current never reached 50 amps at high RPM. An old rule of thumb when sizing alternators was not to exceed 80% of the alternators rating with a constant load. If the constant load on a 65 amp alternator is below 52 amps the alternator is sized sufficient for the car.
For those that want a new alternator for their cars it is my understanding new 65 amp alternators are no longer available and that only the higher output alternators can be purchased new. Keep in mind that some of the Spiders original wiring may not be sized properly for the higher output alternator. This is particularly true of the alternator output wire that attaches to the starter solenoid. I believe a properly rebuilt 65 amp alternator meets the needs of most Spider owners.
Here is a link I think is helpful.

http://cartech.about.com/od/Power/fl/Un ... atings.htm

There is always more than one solution to any problem. In this case rebuild the original or up grading should work.

[Nanonevol]

This is just me, and probably many of you too, but I don't need or want a lot of extra accessories. No A/C, power windows or even extra stereo amp. The only music I want to hear is my twin cam and maybe a staticy AM radio station. You get the picture.

[RRoller123]

I am on that same page. I never turn the radio on.

[vandor]

> The voltage never dropped below 13.5 volts

With the new 95A unit it would be 14.5 Volts even at full load.

[So Cal Mark]

in a perfect world, the oem alternator might be sufficient. But when you consider that every connection has a .1 voltage drop and that's the best case for a 40 yr old car, the oem alternator just isn't good enough anymore. I've yet to hear one person say they were disappointed with the upgrade, especially after driving at night

[focodave]

I am an Electronics Engineer by degree.
Without getting into electrical theory, opinions, arguing about dubious advice, etc -- I will just say this:
The first investment over $100 I made when I bought my car 3+ years ago was the 95amp alternator from Mark.
Best early investment I could have made.
I even tried a rebuilt 55amp alternator from O' Reilly Auto Parts before I bought Mark's unit.
The rebuilt alternator from O'Reilly was bad (winding was open) and I had to argue with some pimple-faced 19-year-old behind the counter who put it on their tester and said it was good, in order to get a refund.
I don't even what to get into that whole story.
Trust me -- get the 95 amp unit -- it's brand new -- do not be scared by others telling you that the 95 amp alternator will set your car on fire -- it's not true.
You'll be glad you bought the 95amp unit -- you can then forget about it -- and then move on to other things you want to fix on your car.
Oh, and if your car catches on fire -- trust me -- it would have happened whether you had a 55 amp alternator or a 95 amp alternator -- the alternator is not to blame....