Of late I've read several tragic truck fire threads wherein alternators were identified as the "likely culprit". I found these especially concerning given that it would appear that my 1990 F250 has its original Ford 2G factory alternator. Got me thinking.

A few questions...
1. What's the longevity on an alternator? If my truck's alt is 35 years old, is it well passed due for replacement?
2. Is the factory 2G alternator as underpowered as folks make it out to be? Is it in danger of failure and/or fire predisposed?
3. What are suggestions for new alternators? Suggested amperage? Solid Mfrs?

Thx in advance for your insights.

Also, is there a thread with suggested updates to OBS trucks? I'd love to not post one of those Found On Road Dead threads because the alt failed and burnt her to a crisp or massive steering failure led to an accident or etc.

 

2gs problem isnt its underpowered, its they are dangerous because of the plug onto the regulator. Upgrading them means more charging amps than they came with stock, a more reliable alternator, and less fire hazzard
Requires mild rewiring

 

I have some experience with a 2g alternator on my "88 F-150. When I first got my '88 F-150 it burned the connection off the alternator where the wires hook to because the previous owner had just replaced the alternator without replacing the pigtail that mounts on the alternator. NAPA gave me another alternator but I had to buy a new pigtail that should have been replaced with the alternator because the pigtail must be replaced if it is the original.

There was a local guy that would repair alternators. He replaced many small things such as the voltage regulator or other little parts many times for a total cost around 25 dollars parts and labor many times. After a while it was pretty reliable for many years. I just replaced that alternator a couple months ago, it contained a new pigtail that just had to crimped on. I didn't get it at NAPA. Cost was about 145 dollars exchange.

Bottom line replace the pigtail that goes with the alternator, hopefully that will stop fires hopefully. You can get a 3G alternator, I don't know how many modifications that takes. I'm sure others will comment tomorrow.

 

If and when you replace your alternator, be patient with the bottom bolt. It took me two hours to get mine out. The bolt seizes into the aluminum body of the alternator, and the threads seize.
I used a 1/2" drive ratchet and a cheater pipe. You can feel the bolt start to twist, and when it starts to turn, you can hear it creak. I also had the top bolt out and was rocking the alternator back and forth.
An impact wouldn't fit in the space on mine, and I'm glad it wouldn't, because I probably would have snapped it off.
After the bolt was backed out of the boss, I used a smaller bolt inserted through the boss from the engine side, to hammer out the mounting bolt.

 

I've never switched one over
Never felt the need
Fire is what insurance if for
I've never actually saw one start on fire myself, just melted wires and that was from a loose connection or from overcharging, a result of not charging a dead battery after alternator replacement or just dead
The loose connection TSB's said to replace the connectors, not the alternators

 

3G swap it, you can have everything on and actually still charge the battery.

Taurus 3.0 units need a reclock, the 94/95 5.0 Mustang do not need the reclock. Notch the bracket, it is beyond obvious when you go to install. Needs two wires to run. One is switched 12V (reuse OE green wire) and run a 4awg or 6awg wire from alt to batt. Plus the VR pigtail...yellow to +B on alt. White is stator plug. Green is the switched.

Best is to find an OE harness off a parts truck for the alt from a 3G truck so fits nice and neat.

 

My truck is stock, have no idea which alternator or plug is on truck.

Why does everyone appear to want more amps?
Is the factory amps not sufficient?

How many amps is my truck drawing?
-(ah, key question I think,...if you have 10 subs and 100 amplifiers that can kill field mice, then sure, get two 3G alternators)

 

The 2G 80A could not keep up at idle with HVAC on high (def/AC on), headlights on, and aftermarket radio on for me. It was low 12s on the DVOM. I guess if you travel on the road it would be fine, never experimented.

The 130A 3G will do that easily, the 95A would too probably. I have probably converted 20 vehicles over the years (Stangs, Birds, TCs, trucks). There is no downside especially since the cost of a 2G is basically the same as 3G.

Ford dumped the 2G for a reason.

 

I replaced mine because it quit working. I kept the one I took off. I stayed with the stock 60 amp.
My truck doesn't have air conditioning.
No stereo, it was missing when I bought the truck. I use that space to hold my sunglasses and safety glasses.
I have plans to rebuild the one I took off.

 

Interesting, I think my 2g is rated for 95 amps. (Reman unit) Voltage is ~14 IIRC. Never had an issue powering anything.

 

Yes, all interesting.

I'm going to hook up an amp meter and get results.

 

Interesting too for me. My 302 had an 80 reman, not 95. Same with the 4.9.

 

Yeah, I was wrong, it's an 80 amp. But at least from the battery, I'm getting 14 volts at idle.

Easily kept up with wipers on high, headlights on, blower max, AC compressor intermittently engaging.

 

On my old 1992 F350 w/5.8L engine the 2G would drop to about 13 VDC on a good day at idle with all the accessories on. No high powered stereo or extra lights. The headlights dimmed and the blower speed dropped down noticeably. Yes, this still happened with new cables. So it was the right time to upgrade. My 3G swap would have been easier if that long bolt would have come out without cutting it. Sourced a new one, notched the bracket. Good to go.

 

The recommendation to upgrade isnt based on amps being necessary, the 3g produces more at low RPM and the 130-140 amp unit is about the same price as the 90 amp units (barely more expensive)
its reasonable to upgrade since every truck has the built in capability to use both
The 4.9 aluminum brakcet just requires tapping out the steel sleeve and placing in the bracket in a different spot for the lower bolt

The TSB did say to replace the connector. as one would expect out of a TSB that was written when the 3g was yet to be released and they were dealing with fires from nothing but the simple unplugging and replugging the connector on the alternator.

I do believe that the plug is called to be replaced anytime that its removed from the alternator. Who wants to do that everytime?
Minimal wiring changes and a junkyard donor and sounds like a possible replacement bolt (would need to replace it if it was ruined on removal either way) are easy to do, gets you a higher capacity charging system, and doesnt carry a fire risk without installing a new plug on the wiring everytime you take it off the alternator.

if you are committed to the 90 amps, just get the smaller 3g.