Best alternator option?

[ArdWrknTrk]

Why would anyone take the time, effort and money to buy a new harness and a fender mounted regulator to get less at redline than even the 95A 3G puts out at idle?

We're not talking about absolute load, because the existing harness can only handle so much.

But we ARE talking about ability to top off the battery after starting.

Or not having your headlamps dim when the turn signals flash.

Or keeping up with the blower and the high beams when crawling through a snow storm.

 

Or when leaving it running to stay warm when it's below zero, while you grab a coffee or pump gas.

Are you telling me that Ford installed a 1G alternator in their vehicles from 1965 all the way to 1985, and it failed to top off the battery after starting?

And it dimmed the headlights when the turn signal flashed?

And it couldn't keep up with the blower and the high beams at the same time?

And it wouldn't stay running when the blower was on in temperatures below zero?

If that is what you are saying, I think you are seriously misleading the original poster.

Littlebeefy said he isn't doing anything "radical" to his truck. Perhaps someone should ask him what he plans to do to before everyone tells him to "upgrade" to a 3G alternator. There is a good chance his current standard-issue 1G alternator is just fine for his needs. My truck came with the 1G alternator along with a feedback carburetor and the EEC-IV engine computer and it worked just fine for over 20 years - and it didn't have any of the so-called "problems" you rattled off. If he actually NEEDS extra amps, then the 3G alternator IS a worthwhile upgrade - as long as he realizes what all he has to do to make it work on his truck.

And it is a lot.

Like Gary already pointed out, he "would like" Moar Power!

And, yes, I'm saying the 1G was marginal (at best) 40 years ago.

It's a boat anchor now.

This thread is titled "Best alternator option?"

The answer is definitely not 1964 technology

[Rusty_S85]

I recommend the 3G as well. Just dont make it as complicated as I am with trying to find a small case 95A alternator with the wide ear spacing cause it may have existed at one time but no longer does. I thought about checking with the local alternator shop to see if they could build me a large case 3G but have it with the 95A rating as I have no plans to upgrade to a serpentine belt.

Also check rockauto, ive seen some brand new 3G`s on there for as little as $85 when I looked a few months ago.

Why does he need a 3G alternator if he has a carburetor? I have a 1G on Lucille and it works just fine. Am I missing something?

If you need more amps, here is another option:

https://www.ebay.com/itm/1965-85-FORD-MUSTANG-100-AMP-HIGH-OUTPUT-ALTERNATOR/264300553258?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

Mainly the cooling. A 1G alternator even if it was internally modified to be capable of producing 100 amps output would you really trust it?

1G alternators dont have the case designed for cooling high amperage. Ive heard some stories that the 75A 1G I have on my '78 Mercury which was a factory option in '78 was about the limit of a 1G before they have a overheating problem.

Like me I dont need a 3G not even with my fuel injection upgrade I could source a 75A 1G alternator for my '78 Mercury and use it on my truck in place of the 65A 1G. But why wouldnt I go with a 3G that has better cooling and for my use will be operating around 25 to 30% capacity vs the 75% capacity of a 75A 1G.

Im sure none of us truly need a 3G, but it is a better alternator that puts out better amperage as well as cools better.

[LARIAT 85]

But why wouldnt I go with a 3G that has better cooling and for my use will be operating around 25 to 30% capacity vs the 75% capacity of a 75A 1G.

Im sure none of us truly need a 3G, but it is a better alternator that puts out better amperage as well as cools better.

Fair enough.

What is the advantage of a cooler running alternator? I have been running my stock 1G "boat anchor" for 35 years now and well over 200K miles without any problems, other than one rebuild.

Using your example, what advantage will someone see running a 3G alternator that is only operating at 25 - 30% of its capacity, compared to a 1G that is operating at 75% of its capacity?

Isn't that sort of like someone "upgrading" their stock ignition system with a "high performance" ignition system for a stock vehicle that never uses the extra voltage?

 

[Rembrant]

Why does he need a 3G alternator if he has a carburetor? I have a 1G on Lucille and it works just fine. Am I missing something?

My ‘84 is still running the original 1G 40 amp alternator and it seems to work fine for me. I don’t notice any issues. I mean all it really runs is the Duraspark and the radio and occasionally the marker lights and signals. I know the 3G is the defacto standard for upgrading so maybe I’ll do it one day, but a new 1G would probably be fine for my old truck as think somebody mentioned previously that you can’t even get the 40 amp units anymore so I’d end up with a 60 or 65 amp unit which would be fine.

 

[kramttocs]

Why does he need a 3G alternator if he has a carburetor? I have a 1G on Lucille and it works just fine. Am I missing something?

My ‘84 is still running the original 1G 40 amp alternator and it seems to work fine for me. I don’t notice any issues. I mean all it really runs is the Duraspark and the radio and occasionally the marker lights and signals. I know the 3G is the defacto standard for upgrading so maybe I’ll do it one day, but a new 1G would probably be fine for my old truck as think somebody mentioned previously that you can’t even get the 40 amp units anymore so I’d end up with a 60 or 65 amp unit which would be fine.

One could always go with the 1 wire Can't get any easier to wire up than that.

 

[Rusty_S85]

But why wouldnt I go with a 3G that has better cooling and for my use will be operating around 25 to 30% capacity vs the 75% capacity of a 75A 1G.

Im sure none of us truly need a 3G, but it is a better alternator that puts out better amperage as well as cools better.

Fair enough.

What is the advantage of a cooler running alternator? I have been running my stock 1G "boat anchor" for 35 years now and well over 200K miles without any problems, other than one rebuild.

Using your example, what advantage will someone see running a 3G alternator that is only operating at 25 - 30% of its capacity, compared to a 1G that is operating at 75% of its capacity?

Isn't that sort of like someone "upgrading" their stock ignition system with a "high performance" ignition system for a stock vehicle that never uses the extra voltage?

Well the advantage is you are not stressing your alternator and wearing it out prematurely. Heat is the number one killer of an alternator.

For me I have a CB, CB amp, I have headlight relay kit, and a dual KC driving light setup on my push bar with 100w bulbs. That is currently the limit of my aftermarket electrical circuits not accounting for the fuel pump and sniper stealth I will be installing with the new engine.

Truck wise its just a plain flare side with a 302 with dealer add on A/C. I saved some power by going with LED interior lights but then I also added Hella ECE composite headlights to run Silvania Silverstar Ultra H4 bulbs.

So for me sure I could probably get by with a 1G alternator. But one thing I did notice that I never tried to see if its a weak regulator or what, at full idle with AC on around 550 rpm the AC blower motor and headlights lose some power. When I go to leave a redlight and I just step on the throttle the moment the rpm comes up slightly my headlights brighten slightly and my blower motor speeds up. That could also very well be the fact I am running at 550rpm without a step up solenoid where OE spec calls for 675 rpm with AC.

But with this in mind and the fact that I will be building a fresh 306 on the engine stand and piecing everything together out of the truck I told myself now would be the time to go 3G. more amps at idle, more amperage than I ever will need which means the alternator should never wear out for me running at such a low demand and I still havent fully decided if I want to add a roll bar in the bed with four more KC lights. I feel even with those four extra lights I would be close to 90A with the truck running with the AC on. Not sure if I would even want to attempt that.

Ideally I would personally like to run the 90A 3G but I cant find a wide ear spacing that our trucks need as they dont seem to exist so my plan as I settled on was the larger 130A large case with one of those 25 second soft start regulators to help stop belt slip since I will be retaining my V belt.

I never really looked to see if it would hurt to run a 75A 1G alternator like listed for my '78 Mercury on my truck. I know that will probably be enough for my truck but doubt it would be future proofed for any other upgrades down the road. But the 75A 1G would be considerably cheaper upgrade for me.

[Gary Lewis]

Well the advantage is you are not stressing your alternator and wearing it out prematurely. Heat is the number one killer of an alternator.

For me I have a CB, CB amp, I have headlight relay kit, and a dual KC driving light setup on my push bar with 100w bulbs. That is currently the limit of my aftermarket electrical circuits not accounting for the fuel pump and sniper stealth I will be installing with the new engine.

Truck wise its just a plain flare side with a 302 with dealer add on A/C. I saved some power by going with LED interior lights but then I also added Hella ECE composite headlights to run Silvania Silverstar Ultra H4 bulbs.

So for me sure I could probably get by with a 1G alternator. But one thing I did notice that I never tried to see if its a weak regulator or what, at full idle with AC on around 550 rpm the AC blower motor and headlights lose some power. When I go to leave a redlight and I just step on the throttle the moment the rpm comes up slightly my headlights brighten slightly and my blower motor speeds up. That could also very well be the fact I am running at 550rpm without a step up solenoid where OE spec calls for 675 rpm with AC.

But with this in mind and the fact that I will be building a fresh 306 on the engine stand and piecing everything together out of the truck I told myself now would be the time to go 3G. more amps at idle, more amperage than I ever will need which means the alternator should never wear out for me running at such a low demand and I still havent fully decided if I want to add a roll bar in the bed with four more KC lights. I feel even with those four extra lights I would be close to 90A with the truck running with the AC on. Not sure if I would even want to attempt that.

Ideally I would personally like to run the 90A 3G but I cant find a wide ear spacing that our trucks need as they dont seem to exist so my plan as I settled on was the larger 130A large case with one of those 25 second soft start regulators to help stop belt slip since I will be retaining my V belt.

I never really looked to see if it would hurt to run a 75A 1G alternator like listed for my '78 Mercury on my truck. I know that will probably be enough for my truck but doubt it would be future proofed for any other upgrades down the road. But the 75A 1G would be considerably cheaper upgrade for me.

Let me bring some real data to the discussion. Here are some specifics from our page here: Documentation/Alternators, and it comes from Jim's test results of his $70-delivered DB Electrical 3G and my calc's from information in the Ford specs:

These are test results for a standard 130A 3G alternator purchased from DB Electric. And the stated output is:

• 106A @ 1600 alternator RPM

• 134A @ 2500 alternator RPM

• 160A @ 6000 alternator RPM

Note that the RPM shown is alternator RPM, but Ford's typical alternator/engine pulley ratio is:

• 300 Six: 2.52:1 for 60A alternators and 2.40:1 for 70A

• 302 & 351W: 3.00:1 for 60A and 2.86:1 for 70A

• 460: 3.00:1 for 60A and 2.86:1 for 70A

• IDI: 2.18:1 for 60A and 70A​

​

To put this in perspective, that alternator will put out 106A at the following engine RPM assuming stock pulleys:

• 300 Six: 635 to 667 RPM

• 302 & 351W: 533 to 559 RPM

• 460: 533 to 559 RPM

• IDI: 734 RPM

In other words, you'll have over 100 amps of output at idle.

[Rusty_S85]

Let me bring some real data to the discussion. Here are some specifics from our page here: Documentation/Alternators, and it comes from Jim's test results of his $70-delivered DB Electrical 3G and my calc's from information in the Ford specs:

These are test results for a standard 130A 3G alternator purchased from DB Electric. And the stated output is:

• 106A @ 1600 alternator RPM

• 134A @ 2500 alternator RPM

• 160A @ 6000 alternator RPM

Note that the RPM shown is alternator RPM, but Ford's typical alternator/engine pulley ratio is:

• 300 Six: 2.52:1 for 60A alternators and 2.40:1 for 70A

• 302 & 351W: 3.00:1 for 60A and 2.86:1 for 70A

• 460: 3.00:1 for 60A and 2.86:1 for 70A

• IDI: 2.18:1 for 60A and 70A​

​

To put this in perspective, that alternator will put out 106A at the following engine RPM assuming stock pulleys:

• 300 Six: 635 to 667 RPM

• 302 & 351W: 533 to 559 RPM

• 460: 533 to 559 RPM

• IDI: 734 RPM

In other words, you'll have over 100 amps of output at idle.

Which I dont want 100+ amps at idle especially with a V-belt. big reason why I am thinking of getting a small case one locally and mock it up on my engine on the stand to see how well it will fit. I know with the 3G those of us with the V8`s can have the alternator slam against the mounting bracket before the alternator fully swings to the shortest setting.

I just can imagine my truck at 100+ amps at idle just ripping my belt to death as it squeals lol.

[Gary Lewis]

Which I dont want 100+ amps at idle especially with a V-belt. big reason why I am thinking of getting a small case one locally and mock it up on my engine on the stand to see how well it will fit. I know with the 3G those of us with the V8`s can have the alternator slam against the mounting bracket before the alternator fully swings to the shortest setting.

I just can imagine my truck at 100+ amps at idle just ripping my belt to death as it squeals lol.

Very few times would the regulator call for full output. But when you start up with a really discharged battery it would happen. And even if you use one of the delay regulators, after a few seconds it'll kick in and go full tilt. Then, since a single v-belt can only transmit something like 90 amps worth of power, you'll have a screaming belt.

I have a dual-belt setup planned for Dad's truck, and have a poly-groove belt on Big Blue. But a single belt isn't going to give full output on a 130 amp alternator. So a small case 3G rated at 95 amps might be a better choice - if you can find it.

[ArdWrknTrk]

Let me bring some real data to the discussion.....

In other words, you'll have over 100 amps of output available at idle.

FTFY

An alternator is not supposed to draw more than is needed to reach its regulators set point.

And I have an LRC integral regulator model, so X seconds ramp up and X seconds to respond to sudden load.

These regulators are available in at least 3 configurations that I know of.