Any reason to not run a 200 AMP alternator?

[MtnHaul]

I need to upgrade the alternator on my 1990 and was thinking about going for the 200 AMP Powermaster since I might get a cabover camper or do some other mods down the road. Are there any potential problems with running a high output alternator if you're not using the bulk of the output most of the time? Yes I will install an appropriate Mega-Fuse and all new wiring and new battery cables will be part of this install. On my '92 I installed the 3g alt that comes with a double v-belt pulley and it has been perfect for the last 7 years so I may just go that route again. With a new 1g alt installed by PO on my '90 I noticed that with defrost, radio, and headlights on that at idle the batteries were quickly drawn down to 12.4ish volts.
Also, opinions on Powermaster alts? I like their starters so I'm hoping the quality is the same on their alts.

 

[IDIBOBS]

There’s no problem running more amps and not using them. But I’d stay away from power master. I’ve installed 100s of them since the 90s. They have come waaay down in quality and durability. I’d just go the 3g route with a life time warranty from a local parts store. That way when when it goes out in 6months or 10years you just exchange it and go no matter where you might be in the country. A few minutes with basic tools in a parking lot and your good to go. A 4hole 3g that puts out 130 amps will be more than enough with good batteries.

 

[Nero]

The alternator will only output what is demanded of it. It'll never hurt to go bigger, but will if you go smaller.

 

[MtnHaul]

There’s no problem running more amps and not using them. But I’d stay away from power master. I’ve installed 100s of them since the 90s. They have come waaay down in quality and durability. I’d just go the 3g route with a life time warranty from a local parts store. That way when when it goes out in 6months or 10years you just exchange it and go no matter where you might be in the country. A few minutes with basic tools in a parking lot and your good to go. A 4hole 3g that puts out 130 amps will be more than enough with good batteries.

Any particular 3g you would recommend? I have been leery of parts stores and their lifetime warranties only because I would rather pay more up front and get something unlikely to fail. Any parking lot repair is more trouble than something that just keeps working.

 

[Nero]

I usually default to napa auto parts, cause lifetime warranty on all starters and alternators. And Ive definitely cashed in on that a few times over the years.

 

[MtnHaul]

I usually default to napa auto parts, cause lifetime warranty on all starters and alternators. And Ive definitely cashed in on that a few times over the years.

A quick search of NAPA "3g alternator" seems to show the Wilson remans as the best option. Pricey at $255 for 130amp already indexed to 3 o'clock, but use the warranty 1 time and it's worth it I suppose.

 

[Nero]

Best bet is to look up a vehicle that came factory with a pivot eyelet 3g alternator.

FORD

WINDSTAR - 1995 - 3.8L
TAURUS - 1990,1991,1992,1993,1994,1995 - 3.8L


LINCOLN

CONTINENTAL - 1992,1992,1993,1994 - 3.8L


MERCURY

SABLE - 1991,1992,1993,1994,1995 - 3.8L


Source: https://www.ford-trucks.com/forums/1506233-130a-3g-alternator-upgrade-on-6-9-7-3l-idi-guide.html

 

[Ruffnek7tree]

I have a mechman 240 amp alternator and it's the bees knees, very quality alternator

 

[MtnHaul]

Well it seems that NAPA basically has one 3g alternator to choose from as far as what swaps from the 3.8L vehicles listed above, so I guess it's an easy choice. I think I'll save the pulley it comes with so I can reclock it and make it look original if I need to warranty it. The local NAPA has been great about essentially a "no questions asked" warranty experience.

 

[rreegg]

Not sure if it’s a 3g but my truck got a Napa alternator put in 2013 I think. I have only glanced at the sticker. No issues so far knock on wood.
PO used Napa parts throughout which was encouraging as a buyer.

Surprised to hear power master alts are not recommended as their starters are said to be high quality

 

[MtnHaul]

Not sure if it’s a 3g but my truck got a Napa alternator put in 2013 I think. I have only glanced at the sticker. No issues so far knock on wood.
PO used Napa parts throughout which was encouraging as a buyer.

Surprised to hear power master alts are not recommended as their starters are said to be high quality

Yeah it's always a bummer to hear a formerly good company may have taken a downturn. The issue of being able to handle warranty replacements/repairs at multiple locations and in-person is pretty huge. I have found older posts regarding P-Master and warranties where customers had to ship the failed unit back to Powermaster at their own expense and then wait around, yadda yadda, and then still not always achieve a satisfactory outcome.

 

[Old Goat]

Well for what it`s worth, Iam using a Power master Alternator 130 Amp. Put it in 3 years ago. been running just fine.
I did add a Stewart Warner Volt Meter, installed it right in the middle where the Tach would go. This is on my Bull Nose.

It is a one wire set up. Pos 6GA wire to the battery and Neg 6GA to the negative post of the battery. Puts out a good 14V, unless the Lights, heater are on then drops down a bit.
When I start the engine first thing in the morning, doesn`t show a charge, till I goose the engine a bit, then kicks it on I guess.
From what I read about one wire set ups is common.
Haven`t had any problems with it, but anything will eventually cause us problems.
I got rid of the Voltage regulator and other wires.
Bought it from https://www.speedwaymotors.com/shop/alternators~14-14-465-2412
Chrysler has used one wire alternators for quite a while from what I have read. Quite common.

What got me to change to a one wire, My 84 John Deere 950 had an electrical problem, Burned wires from the Head Lights, back towards the Ignition Switch, then a few others. Then I think to the Voltage Relay etc...
Called the JD Dealer about the wire harness....Bring it over.
Mechanic said it was a POS and get another one...but NLA.
and to use JD Gold plated parts...yeah right.
A guy in Portland, Or. was parting a couple of these 950`s and I bought both harnesses. Almost as bad as what I had.
Steiner Tractor sell vintage tractor parts and found a one wire Alt., replaced the Starter etc...ripped out unnecessary wires etc...
Works great.
The JD Maint. manual has a great fold out of the wiring in colors which make it easy to follow and see exactly where all the wires go. Wish the stupid way Ford has theirs was the same way, sure would make it easier to follow, instead of the block diagram thing they have.



Goat

 

[IDIBRONCO]

When I start the engine first thing in the morning, doesn`t show a charge, till I goose the engine a bit, then kicks it on I guess.
From what I read about one wire set ups is common.

I used to have a 1975 International pickup that did the same thing. It used a standard AC Delco alternator like the Chevrolets of the same era had. I thought something was wrong with the alternator. I knew a guy who tried to takeover a mechanic's shop that still had inventory in it. He had a high output 70 amp alternator. He sold to to me for next to nothing. I was amazed when that alternator did the same thing. I just got into the habit of giving a small engine rev after I started the engine so that the alternator would charge.

 

[IDIBOBS]

Yes power master alternators are turned on by higher rpm’s. Usually around 1000 depending on the pully set up. But I’m pretty concerned it’s dropping under such a light load. Your lights should be less than 20amps. Your heater doesn’t take any electricity at all. I’m sure you mean the blower fan. And that is also 10-20amps max. A power master should put out 14.1volt or more at 150-200 amps. My 130amp g3 can idle at 650rps with head lights on high beam, running lights, 5 led light bars for work lights, hooked to a trailer full of lights, blower motor and radio with amp and it sits right at 14.3v

 

[aggiediesel01]

Just make sure the output wire of the alternator can handle the current the alternator can produce. If you’re into DIY check out this place for a high current rebuild option. I’ve done several high current 3g ones and not had any troubles with them yet. If you haven’t converted to the 3g yet I believe you have an external regulator to control the alternator output. So you may need to upgrade the regulator as well.

Also look into getting a slightly smaller pulley to speed up the alternator. At idle these engines run at the very bottom of the speed current curve for the 3g and even at redline they don’t come close to the top end. So speeding up the alternator shaft, really helps it produce more power at idle.

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