altenator
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Freshman User
Joined: May 2013
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altenator
Ive been noticing lately my lights have been diming when sitting at idle im prob gonna replace the alt before the winter i was wondering is their anything i have to do to go from a 60-65 amp alt to possibly a 70 amp i was told that the 70 was a option for my 83 f100 (l6 ,auto)
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
The alternators on these trucks put out very little if any charge @ idle speeds, so it is not uncommon for lights to dim, especially if the blower or A/C is being used. Have the alternator output checked. Normally, auto part houses will do this for free.
Make sure the idle speed is correct. If just a little low, it will add to the dimming.
You also can read [use the "search" feature] about 3G alternator swaps.
Make sure the idle speed is correct. If just a little low, it will add to the dimming.
You also can read [use the "search" feature] about 3G alternator swaps.
Moderator
Joined: Jan 2001
Posts: 56,992
Likes: 2,741
From: Virginia
There is the possiblity that the larger output alternator is also a little bit physically larger. Sometimes because of this the brackets may not fit correctly. I am not sure on this in your case, so just check it out of you decide to do it.
Like was said in the previous post, most alternators do not put out much at slow speeds, the max amperage can only be used at higher engine speeds. A larger alternator may not help your problem. The 3G is designed to have more output at lower speeds, but it's going to require bracket work and a little re-wiring.
Raising your idle speed will help your problem. When I put a snowplow on my 1980 f150, at idle it would not pick up the plow. All I had to do was raise the idle speed just a little bit and it worked fine. It only had a 65 amp alternator.
Like was said in the previous post, most alternators do not put out much at slow speeds, the max amperage can only be used at higher engine speeds. A larger alternator may not help your problem. The 3G is designed to have more output at lower speeds, but it's going to require bracket work and a little re-wiring.
Raising your idle speed will help your problem. When I put a snowplow on my 1980 f150, at idle it would not pick up the plow. All I had to do was raise the idle speed just a little bit and it worked fine. It only had a 65 amp alternator.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
The alternators on these trucks put out very little if any charge @ idle speeds, so it is not uncommon for lights to dim, especially if the blower or A/C is being used. Have the alternator output checked. Normally, auto part houses will do this for free.
Make sure the idle speed is correct. If just a little low, it will add to the dimming.
You also can read [use the "search" feature] about 3G alternator swaps.
Make sure the idle speed is correct. If just a little low, it will add to the dimming.
You also can read [use the "search" feature] about 3G alternator swaps.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
I seem to be the 3G maven (or shill) on this forum.
Tell us about your current '83 1G and we can help you with more charging at idle than you are currently putting out at redline.
A 95A 3G is no bigger than your current alternator. (135mm diameter)
The 130A is a little bigger @ 148mm.
13mm difference is a little more than 1/2", but I think the 4.9l needs the wider 8.25" C-C spread mounting ears anyhow.
Tell us about your current '83 1G and we can help you with more charging at idle than you are currently putting out at redline.
A 95A 3G is no bigger than your current alternator. (135mm diameter)
The 130A is a little bigger @ 148mm.
13mm difference is a little more than 1/2", but I think the 4.9l needs the wider 8.25" C-C spread mounting ears anyhow.
Posting Guru
Joined: Apr 2011
Posts: 1,636
Likes: 5
From: Orlando area
The alternators on these trucks put out very little if any charge @ idle speeds, so it is not uncommon for lights to dim, especially if the blower or A/C is being used. Have the alternator output checked. Normally, auto part houses will do this for free.
Make sure the idle speed is correct. If just a little low, it will add to the dimming.
You also can read [use the "search" feature] about 3G alternator swaps.
Make sure the idle speed is correct. If just a little low, it will add to the dimming.
You also can read [use the "search" feature] about 3G alternator swaps.
http://alternatorparts.com/alternator-pulley-size.html
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pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
Smaller pulley = less area for belt friction.
Also be aware of overspeeding.
RJM used to have warranty disclaimers for bearings and slip rings due to rpm's.
The 2G's were fine for a first shot at an internally regulated alternator.
But the charge plug issues and poor low rpm output caused Ford to do the same upgrade we are suggesting.
Also be aware of overspeeding.
RJM used to have warranty disclaimers for bearings and slip rings due to rpm's.
The 2G's were fine for a first shot at an internally regulated alternator.
But the charge plug issues and poor low rpm output caused Ford to do the same upgrade we are suggesting.
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Moderator
Joined: Jan 2001
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From: Virginia
I am going to bring this up again. If all you want is more charging at lower rpm, the 3G woud probably be a good choice. If you are going to run electric fans, lights and other power hogs, and actually need over 100 amps from the alternator, a single v-belt will usually start slipping. If your battery is a little bit low, you may still get some belt squeal from the 3G as it's trying to bring the battery back up. They have some special regulators that try to bring the 3G in slow to avoid this, but to get the full benefits from the this alternator, you need dual v-belts or a serpentine belt.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
Dave is talking about Load Response Control (LRC) regulators.
They were developed to solve erratic idle in underpowered and luxury cars.
Basically soft start using pulse width modulation.
Available in 2.5, 6 and 10 second rise time.
These can help reduce belt squeal by ramping up the load instead of applying it all at once.
They were developed to solve erratic idle in underpowered and luxury cars.
Basically soft start using pulse width modulation.
Available in 2.5, 6 and 10 second rise time.
These can help reduce belt squeal by ramping up the load instead of applying it all at once.
Lead Driver
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
From my understanding the 1G alternators were externally regulated and the 2G and 3G were internally?
I am just curious as my '82 F150 is externally regulated and I am kind of curious what series of alternator this is.
I will be adding some aux lighting but I did do LED conversions on the interior lights which will help out my power consumption some, but I planned on converting my sealed beam bulbs to composite bulbs and using more modern H4 bulbs.
Just wondering to myself if the stock alternator could handle running two H4 headlight bulbs on the high beam setting. If they can then I would question if they could run four more mounted on my roll bars that are H4 bulbs on high beam.
I am just curious as my '82 F150 is externally regulated and I am kind of curious what series of alternator this is.
I will be adding some aux lighting but I did do LED conversions on the interior lights which will help out my power consumption some, but I planned on converting my sealed beam bulbs to composite bulbs and using more modern H4 bulbs.
Just wondering to myself if the stock alternator could handle running two H4 headlight bulbs on the high beam setting. If they can then I would question if they could run four more mounted on my roll bars that are H4 bulbs on high beam.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
The truck came with a 1G, with about 60 - 65 amps total output at higher RPM. At 12 volts and a high beam of 60 watts you are looking at 5 amps/light. If you are running 6 of them you'd have 30 amps of draw in those lights, leaving about that much for everything else. If the heater or A/C is on full tilt that'll just about take it all when the other lights and the engine are taken into account. In other words, if everything works perfectly it should work, but when does everything work exactly right?