Best alternator option?

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

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.

Rusty_S85 wrote

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?

LARIAT 85 wrote

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.

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.

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.

Gary Lewis wrote

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.

Correct.  Thats why I really wanted a small case 95A but everyone says the narrow ear small case poses a problem on truck brackets not being able to swing enough in.  Im thinking about possibly just giving it a try locally that way if it doesnt work for me I can return it saying its not right and get my money back.

I probably would still get a soft start regulator even if I do get the 95A one to work properly in function.

I did look at rockauto just to see how much a 75A 1G is like on my '78 Mercury.  Apparently they dont offer 75A anymore but my 1G case is stamped 75A on it.  Most I found was 70A and 78 Mercury 351W or 82 F150 302 they both have the same exact listing.  Kinda makes me wonder if a 70A 1G would be enough for my truck.  Would save me the money over a 3G upgrade.  But then the other part of me is like, but I really want to add more lights or maybe have my OE radio upgraded internally or maybe a behind the seat amp and sub to get some bass.  All of which I feel would put me way too boarder line with a 70A alternator.

I did consider trying to run a double belt but not sure how that could be done considering I have one of those bolt on crank pulleys for my dealer A/C.  I did look online as I did see some brands used to sell pulley system upgrade that retains V belts but converters alternator to a narrow multirib belt.  But nothing for a ford and probably would throw my outer pulley off.

But you are right though, I seen 100A as the absolute highest a single V belt can handle but this also is taking into account of having the belt pretty tight.  I just know even with my EFI I dont think I need more than 95A, thing that has me concerned is if it will fit and swing far enough to get the correct sized belt on or do I have to get some custom sized belt which will require me to keep a record of it in the truck in the chance it breaks or gets thrown off.

amperage will be in line with what is needed based off voltage being supplied.

On the regulators I believe the one I have saved is supposed to be a 15 or 25 second ramp up regulator, maybe im wrong on the time but it is the longest ramp up regulator I found and the way I understood it was over that time period the alternator would slowly build amperage output up to what the system needs to charge.

I don't think there is a ramp over ten seconds (at least I haven't found it)

But I don't get a chirp or any squealing from a single belt properly tensioned.

I think as the belt starts spinning it slips less just because it wants to be round instead of wrapped around the sheaves.

Gary tells about his dad hammering a rat tail file into the pulley.
No one needs to abuse their bearings like that.

I believe pulley wrap also plays a part.  I know on mine the belt goes straight from the crank to the alternator and not around anything else so my belt wrap is around some 180* of the pulley.  This would provide more tension than a belt that is only wrapping around some 90* of the pulley.

I know I make it hard on myself with the whole 95A vs 130A struggles I have with myself.  I just know I personally want more out put more volts at idle but no belt slippage, that squeal just bothers me too much.  Not to mention if I nail the throttle and it goes to squealing while I am at full throttle, I fear there could be a situation of throwing the slipping belt which could take out my water pump/powersteering belt.

Why I think I will just try to source a 95A alternator locally and try it via mock up see how it fits.  I just know online you cant get them that easy, 91-93 Taurus 3.0 is supposed to be a 95A alternator with the wide ear 8.25" spacing.  Every where online lists 130A with the wide 8.25" ear spacing as it seems most places have replaced the 95A with the 130A.

I don't know why it would go to slipping if you matted the throttle?

There's no abnormal load on the alternator, and I know I don't often have the room or gears to hold the pedal down for the 10 seconds it would take for the alternator to fully load anyhow.

Honestly I dont think there will be slippage but I have seen lots of people mention it and it is always at the back of my head.

I feel with 180* of belt wrap in this case with a good amount of tension and with the longest delay regulator there shouldnt be any slip.  But I am still fearful that it may happen or possibly throw my belt if it happens bad enough.

I know currently without EFI I think my truck is only pulling some where around 40A of total power with everything active.  With EFI I doubt it would be much over 50-55A and I could probably get away with a 70A 1G alternator but it kind of limits me on future expansions if I decide to add underhood lights or rock crawling lights along the underside of my truck tied into the alarm or door jamb to help illuminate around my truck when in the middle of a dark field, or if I decide to throw more auxiliary lights on my truck and decide to stick with the Halogen bulbs instead of going with the KC LED versions since I havent been able to find a good comparison of the 100W hallogen lights to the LED versions.

Why I kinda thought at one time go with the 130A since it has the 8.25" ear spacing that will fit our V belt trucks and just down grade the fuse for the alternator charging circuit to around a 125A since I am pretty sure even with a tight belt the fuse will never blow as the alternator will slip first.

Lots of great info here, guys. I think that I would be good with a 90-95 amp G3 unit, but I'm going to see how hard it is to upgrade to a 130 amp. I'm also a little concerned about the slippage, but want to make sure I have enough power to run lights, an amp and potentially other electronics.

In my experience with the finicky electronics on my 928, bad things start to happen when current drops too low. It may not be a big deal when your your lights dim a little, but that is a reflection of what is happening to other equipment like your fuel pump, for example. Regardless of the inherent flaws in the design of the 1G and 2G (of which I understand little) if the alternator is giving you "just enough" power, that means that there are probably times that it is falling short and overtaxing some components. I personally don't think that many pre-1990s vehicle had a sufficiently robust alternator and all of them could use an upgrade. Except for British cars which should probably have all of their electronics thrown away completely.

I did end up having a falling out with my mechanic over this one. He refused to do the upgrade so I'm now looking for another mechanic in the Atlanta area. Let me know if you have a recommendation. Probably gonna post the request as a separate thread.

Chad, if you're concerned about the little 'chirp' on startup just be sure to get one with a LRC regulator.
You won't have to run the belt too tight and you won't ever hear that.

PS, you might ask Dorsai/Matthew since he's in your area

Littlebeefy wrote

I did end up having a falling out with my mechanic over this one. He refused to do the upgrade so I'm now looking for another mechanic in the Atlanta area. Let me know if you have a recommendation. Probably gonna post the request as a separate thread.

Now that is interesting.  Did he give a reason WHY before he refused to do the "upgrade?"  

You are familiar with The Prince Of Darkness?

I don't have a recommendation for anyone in Atlanta, so you are probably right to start another thread to get input.

As for the alternator being able to always provide enough output at idle to keep the battery voltage at 14.4, the 1G can't if you are running the blower on high and the headlights at the same time.  In fact, I'm not sure it can w/o the blower motor on High as all the ones I've been around have had the headlights dim at idle, which means the voltage dropped.

And I don't think the 2G can as the info I've seen on its output shows it isn't much better than a 1G.

The real revolution came with the 3G.  It has more output at idle than the others have at full tilt.