How to tell if your alternator has an internal regulator

JohnJL · 01-14-2006, 03:46 AM

It you know, please insert answer here:

Please also note where the external regulator is located in an 82 SC, if it had one...

Thanks!

Laneco · 01-14-2006, 04:33 AM

We have a 1982 SC and the alternator is definately internally regulated. According to the Bentley manual pages 270-10 and 270-11, 1978-1981 are externally regulated (voltage regulator) and 1982-83 are internal.

If you had an external regulator, it would be on the left side of the engine bay beside the ignition box.

angela

Early_S_Man · 01-14-2006, 04:37 AM

The 1982 USA SCs came with alternators that had internal regulators, and three terminal on the back of the alternator ... D+/61 for the Blue wire, B+ for the Red cables, D- for the Brown cables.

Some ROW 1982 SCs may have still had the separate regulator, which was mounted on the electrical console on the left fenderwell of the engine compartment ... Four terminals, the above plus DF [Dynamo Field] for the Black wire ...

Jadams1 · Jadams1's Garage

If you have an external regulator it will look something like this.

john walker's workshop · 01-14-2006, 08:06 AM

if it doesn't have an external reg, or if it's been left there but unplugged, (not a good idea), chances are good that it's an internal. lots of older ones have been updated.

mikemdd · 01-14-2006, 09:09 AM

What are the advantages/disadvantages of internal vs. external. It would seem that the external would be easier to service.

Thanks

Mike

Lorenfb · 09:23 AM

"What are the advantages/disadvantages of internal vs. external. It would seem that the external would be easier to service."

Advantages of internal:

Only to the car manufacturer - a simple overall application

Disadvantages of internal:

1. less reliability - regulator now runs at basically the head temp (911)
and in other apps at the temp of the alt
2. lack of ease of replacement or troubleshooting

The Paris-Rhone alt. (internal reg) used to replace the earlier 911SC Marchal alt is the least reliable of all 911 alts. ('65 - '98). This should answer all issues about
an internal versus an external reg alt.

An easy way of determining an internal versus an external on a 911 is the
allen slot in the shaft on an internal.

Early_S_Man · 01-14-2006, 10:12 AM

Now that I think about it ... the internal regulated alternator shafts are M17 nuts rather than M16 of the Marchals ... so, all you have to do is put a caliper on the shaft threads.

JohnJL · 01-14-2006, 01:38 PM

Hmmm... here's a pic of the backside of the alt. THe shaft is 16MM.

The engine is from a US 82SC. The car is a Japanes 82 SC. The car appears not to have any external regulator. I am selling off the stock Japanese 82 engine that came in the car intact, so I am hoping both alternators are of the same type. That is, I hope the one pictured below is internally regulated since I haven't found any regulator mounted in the engine bay.

Early_S_Man · 01-14-2006, 01:56 PM

John,

That is a 70 Amp 980 Watt Marchal alternator ... there should be a regulator on the electrical panel just like the one Jadams1 posted the pic of ...

JohnJL · 01-14-2006, 02:09 PM

Doh...no reg, just the rear defroster relay..looks like my engine came with an alt needing an external regulator, but my donor car came with an engine with an internal regulator...

Anyone have a spare regulator they want to part with? I know Pelican sells them for $30, but I am still waiting on my order placed December 15 :-(