1980 911SC Alternator bad?

[bairdc3]

I have a 1980 911SC. While out driving the radio went out and the eventuallly the car died. I charged the battery (via a jump start and made it the 3 miles home. Question what could be the problem.

1) Car has the Marchal Alternator. (Pull it out today)

2) No Light when ignitionkey was turned on, but not turned over (started). (Can I check this now that I have the Alternator out?)

3) Tested with Voltmeter at the battery while car was running, meter indicated
under 12v.

4) Where exactly is the Voltage Regulator and how can I test too see if this is the problem?

5) The battery is an Optima relaitively new.

6) No one can test the alternator (PepBoys, Autozone, Kragen) as the fan causes them problems hooking to their Machine.

Before I drop 400+ for new alternator, fan shroud etc, etc, any ideas.

I am assuming I should just get a new Alternator and regulator?

[tab tanner]

The regulator is in the alternator I think. I have a new/rebuilt alternator for a 84-89 carrera if you can use it P.M. me if you are interesed Thanks TAB

[stealthn]

Take the alternator to a small shop and get it refurbished for @$50, new bushings, bearings, etc. Should be good for another 50k miles, unless of course if its' toast.

[nostatic]

With the car running you should see 13V at the battery plus or minus a bit. 12V is too low, and would be one sign of a tired alternator. If yours hasn't been changed, you have an external voltage regulator (they switched design in '82). If you want to buy a new one, you are stuck with the newer design with the integrated VR. I elected to get a rebuilt old style and keep my separate VR.

[bairdc3]

It's definetly does not have the integrated VR. It says Marchal on the back and has only 5 connections 4 with screws (Red, Blue, brown and multiple browns. And a black DF wire that plugs in.


If I have to go with the new Altenator style. Where is the OLD VR and how do I bypass it? In the tech bulletin it states fasten plug onto wire harness?

Also where do you get the air Duct shroud, Resistor and other pieces needed, for the conversion.

[targa80]

Did the alternator light come on while you were driving it? If the alternator was not outputting voltage then the light should have come on. The other problem is the bulb has blown. I believe that if it is blown the alternator will not charge. The circuit with the alternator light is used as an exciter for the alternator field windings. With the engine not running and the ignition on the light should come on. Even if the battery is low the light should still glow a little. If the alternator is bad get it rebuilt and avoid the mod (atleast that's my opinion). The voltage regulator is mounted on the electrical panel on the left side of the engine compartment. It has a plug with three wires. There may also be a noise suppressor installed between the voltage regulator and the connector from the alternator.

[hgray]

There was a good discussion about a month ago on alternators. My recall was that some of the more knowledgeable electrical folks thought the Marchal was a part worth keeping.

The thread started out asking about a new battery. I found it doing a search for 'Marchal'. The link is below (I think).


Huge battery in 86 Coupe

[304065]

There are a couple dozen posts in the last month on this- use the "search" feature and you will uncover more than you could possibly want to know about alternator theory, problems, and fixes.

Anyway your problem is the warning light bulb. Since you've already taken the alternator out of the car, here's how you test it. First, charge the battery overnight. Second, turn the ignition on and touch the BLUE wire that connects to the back of the alternator to the ground on the engine block. The warning lamp should glow brightly. If it doesn't, there's your problem. DISCONNECT the battery then and put some masking tape over a butter knife or other dull blade, and GENTLY pry your oil pressure gauge out. You can then replace the warning light bulb and re-test.

Good luck!

[bairdc3]

Thanks for all the help appears to be the Alternator after all. I did what John suggested and as soon as i touched the blue wire to the engine block the Alt lamp lite up just fine.

It also appears that I am only going to be able to get the newer style alternator (integrated VR). Does anyone know where to get the other items that the tech bulletin states that I need.

Airduct
Resistor
bushing.


Also what exactly is the best method
for fastening the plug from the VR onto the wire harness. Any pics of this done would be helpful.

[Lorenfb]

Internal reg. alt. is a mistake! Buy two if you go ahead with the internal reg. one.
Keep one as spare in the trunk. That is the worst alt. Porsche ever used. It's
just 5 amps more than the original one. They tend to intermittently overcharge.

Get the original rebuilt properly, and it will last another 100K + miles.
Also, if you have a reg. problem, it's easy to replace with an external reg.

[bairdc3]

Thanks Loren, do you know of anyone who rebuilds the Marchal? I have called 3 places in Sacramento CA and they all did not want too touch it, they kept quoting the Paris model.

[5speed]

Keep calling the rebuilders in your area, just expand your search area. All the applications books they have will say Paris-Rhone, they insisted I had the wrong alternator. I ended up driving to a hole in the wall place two hours away to get mine rebuilt and it took a month to find the place. After I reinstalled the alternator it took me another month to find a 68ohm resistor for the warning lamp. Two months and the warning lamp still glows when it idles.

[Lorenfb]

The 911SC doesn't need a resistor like the early cars with the 55 amp Marchal.

Call Tom at Pelican. He should be able to help with a rebuilt alt. They have
many sources. Just because it's not should on the Pelican web site don't
assume that it's not available from them.