Quick Alternator Question 1988 7.3

[CBRF3]

If you really want to go big, here is a 150A one...

Plain:
https://www.oreillyauto.com/detail/...ernator/847141/6594808/1987/ford/f-250?pos=11

Black:
https://www.oreillyauto.com/detail/...ternator/857140/6594810/1987/ford/f-250?pos=8

Chrome:
https://www.oreillyauto.com/detail/...ternator/837140/6594804/1987/ford/f-250?pos=6

Plain but different external fan:
https://www.oreillyauto.com/detail/...ernator/847140/6594807/1987/ford/f-250?pos=11

The last one is a 12si the others are 10si


you dont want to go a 10si over 90 amp the cooling isn't there as i explained earlier and will cause longevity issues the 12si is the one you want for above 90 amp

https://www.amazon.com/Alternator-Delco-Pulley-HYSTER-1983-1990/dp/B00SG0K5EW

12si alternators have a different cooling fan and different in the back of casing a bit to allow for more airflow directly over the bridge rectifier and stator / internal voltage regulator

 

[HammerDown]

Well that did'nt last long... the recent replacement alternator is starting to act up (flicker the dash battery light) .
Why does sh*t always happen when it's freezing cold or sweltering hot?

 

[david85]

What are the rest of the gauges doing? Is the alternator still charging?

If you have hand held volt meter, it might be worth monitoring it while that light acts up (analog would be best to see any voltage drops more easily, but digital will still work). I would also double check all the wiring connections around the alternator that were recently disturbed. Grounds on the engine block as well.

And for what it's worth, I think my 1986 still has the original Motorcraft external regulator! I don't know the alternator size, but it's not original.

 

[dan-o]

My 1989 has an external regulator and rectifier. I assume due to the fact that it's a 200 amp alternator. It is the ambulance package so it used t run a boat load of stuff that I don't neeed anymore. When I got the ambulance I had to rebuild the alternator.
Now, I'm thinking of downsizing to get rid of the regulator and rectifier to give me more space in the back box/camper section and get rid of sixty pound of excess wire.

 

[IDIBRONCO]

Why does sh*t always happen when it's freezing cold or sweltering hot?

I like to blame it on that Murphy fellow. Sometimes I really hate him.

 

[Big Bart]

Well that did'nt last long... the recent replacement alternator is starting to act up (flicker the dash battery light) .
Why does sh*t always happen when it's freezing cold or sweltering hot?

Old and long thread so did not read all of it. Did you replace the regulator with the Alt? If not perhaps it is your regulator this time.

 

[Black dawg]

over the 25 years I have been driving and working on these trucks, these alternators and external regulators have been nothing but trouble.

3g is the answer.

 

[HammerDown]

Old and long thread so did not read all of it. Did you replace the regulator with the Alt? If not perhaps it is your regulator this time.

I replaced the regulator with a $35.00 epoxy sealed unit... and out of the box it didn't work!
So, I installed the old regulator and it worked just fine.
The replacement alternator is failing like the 18 year old one did... it randomly flickers the battery light on the dash as in it'll work for and hour or so then flicker the battery light then it's ok for a bit again. Until it just dead fails.

 

[HammerDown]

over the 25 years I have been driving and working on these trucks, these alternators and external regulators have been nothing but trouble.

3g is the answer.

Original owner here, since new I only replaced the OEM alternator and regulator once, about 18 years ago.
So, I haven't had your bad luck with the charging system.

 

[Kizer]

I only replaced the OEM alternator and regulator once, about 18 years ago.

What parts store do / did you buy from?
I've had TERRIBLE luck with NAPA alts.

Thank you.

 

[TNBrett]

What parts store do / did you buy from?
I've had TERRIBLE luck with NAPA alts.

Thank you.

In my experience generic starters and alternators from any parts store is a roll of the dice. The best thing is finding a good local shop that rebuilds them.


Sent from my iPhone using Tapatalk

 

[Kizer]

The best thing is finding a good local shop that rebuilds them.

Local shop is terrible ... I guess I should learn how to do it myself.

 

[Black dawg]

Original owner here, since new I only replaced the OEM alternator and regulator once, about 18 years ago.
So, I haven't had your bad luck with the charging system.

I really think it has to do more with the aftermarket regulators being junk than the alternators, the best luck I have had is with finding oem regulators in junkyards and using them. Just converting them all to the 3g has greatly simplified this for me. And they charge way better.

Interesting on the regulators, as ford has used basically same one since the mid 70s, and the only ones I have had trouble with are the ones on the diesel pickups.

 

[Big Bart]

Sounds like your brushes are worn out.


Either my local O'Rielley's or Napa can still order the Motorcraft external regulator. (Can't recall. Usually have it later in the day or next day.)


Also Powermaster makes some great rebuilt heavy duty alternators. They are pricey, but if you are going for longevity I would take a look at them. Popular in the Jeep community for taking a beating, getting dusty, and high loads.(Winch, lights, etc.) You may have to put your double pulley on it to use it. They tend to sell most alternators, just not with all options. (Back plate at 3 o'clock instead of 12' o'clock. Double pully VS single pully.) The alternator is the same, just not set up the same or with the same pully. But this all can be done by the buyer.


http://www.powermastermotorsports.com/


If doing the Alternator adding a $30-40 regulator just makes sense. If nothing else cheep insurance that both will go the distance again. Some auto parts stores can still test these external regulators to confirm good or bad, but I would recommend just replace with a new Motorcraft one.


Ditto to rebuilt auto parts store alternators are hit or miss. O'Rielly only had their cheaper chicken house brand for my sons 67 Galaxie. First one had a bent fan and was out of round. Second one had a loose pulley. Third one the fan spun when you held the pulley. We said heck with this junk and went to our local independent auto parts store. Theirs at least did not have any visible issues. We will see how it holds up. What happened to pride of work and quality control????


We had a great alt/starter rebuilder locally until recently. He did marine and automotive applications. I believe he closed down due to a rental increase and decided to retire. (Had already moved once a couple years earlier.) Went to the other guy, was not super impressed with his shop or work. So I will have to find another good rebuilder.


We also lost a great trailer repair shop, developer bought the property, owner could not find another property around for close to the same rent. He went to work for another trailer shop a few cities over. We ended up loosing a key small business withe tons of knowledge for apartments or town homes adding to the cities already heavy traffic!

-running.89858/

 

[catbird7]

Original owner here, since new I only replaced the OEM alternator and regulator once, about 18 years ago.
So, I haven't had your bad luck with the charging system.

Just before changing to 3g, mine was doing the same thing and it was the grey plastic plug that pressed into the alt. When the light flickered, if I opened the hood and had someone watch the light while I pressed on the plastic plug, the light would go out. Rather than fix the wiring plug, I swapped to 3g and glad that I did. It's an easy swap.