VA911

HI! ok i have a 79 SC and the alternator has gone bad. it has an external BOSCH reg RE55 part number 9 190 067 008. What type of alternator is it? I am rebuilding it at the moment and the guys cant work out what alternator it actually is and where to get the rectifiers from? part numbers anyone or can i use rectifiers from any other model? diods need replacing as well.
Problem started with tacho bouncing. Then car cut out about 5 or 6 times and i found that after it stoped cutting out it wouldnt start (ie not enough charge to turn starter). Has this thing happened to anyone else.
oh BTW the car is an original Ausi delivered car
THANKS!

theiceman

I think it is a Marschall alternator. I have a 78 with the same one. Mine just needed bearings.

VA911

Thanks for that. the guys thought it may have been a motorolla?? or even a bosch. possibly this may help.
would a bad alt cause the problems i had?

theiceman

A bouncing tach is the first sure sign of the charging sytem failing . I would first check every ground on the car , but failing that you are looking at an alternator. you should be able to tell by putting a meter on it but sounds like you are already past that point.
The problem is you may not get another , you may have to update to an internal type regulator on an updated alternator, these means changes to the air shroud also. Pelican forums has the write up as I was prepared to do this when mine had trouble. Too bad you are so far away as I would pay for youto ship your dead one to me if you did upgrade, tht darn nut is impossible to find on the older ones, it is a special thread.

I think you may have a hard time finding a diode pack for a 25 year old alternator, maybe you can just find some high powered diodes and have them spot welded in , I am pretty sure they are not soldered

Good luck and keep us informed

PS some info I just dug up . probably referes to the update

911 1966-77 Alternator Not Available
911SC 1978-83 * Alternator 911 603 120 DX
911 603 120 04 Paris-Rhone(Valeo)
A14 N 11
*See Technical Bulletin Group 27, Number 82-02 in technical Marchal 712 330 02
bulletin book A, part number PNA 000 056, page 283. Marchal 712 237 02

Thanks

VA911

Ok i have more news!!!
diode pack and accumulator plates are avaliable from porsche parts here. at a scary amount of cash.. ie could almost buy a genuine new alt... can still buy the genuine new alt. once again could rebuild most car engines for that much. I have however found an accumulator plate that fits and is going in now (with a minor modification to the alternator housing, that is drilling out the smaller holes where the threaded bolts come through and connect the wires to the accumulator plate). i will post what the part number is (i know that they bosch ones though). diodes can be replaced easily enough.. and yes i think they are spot welded.
Hope i get it back tonight so i can put her back together and blast in her tonight!!!!

theiceman

Post some pics of the project if you can , I would be really interested given I have the same alternator ..

What exactly is an accumulator plate ?

cobalt

I am going off memeory of more than 10 years ago, but IIRC the 79's used one of 2 alternators Bosch or SEV Marschall. Odds are it is a Bosch.

Now I had a problem with mine a long time ago. I though the diods had gone but I found that after years of use their was carbon buildup on the armature makeing intermitent contact, I also found one of the brushes to be at the end of its length causing the arching that lead to the problem. Now you can tell if the diods are shot and just the smell alone is a give away. But you might want to try checking the armature and brushes first.

rbuswell

If you plan to keep the car you might consider the AASE Sales Bosch parts unit. Built in Australia and it is stout compared to the OEM alternator and good for 95 amps. Built to last and the people are pros that give personal attention. I was very pleased. I believe you can replace with an internal VR unit without a problem but they'll know. Be prepared to pay some serious bucks. Call 714-745-1162 or email at sales@aasesales.com.

Lorenfb

"I am going off memeory of more than 10 years ago, but IIRC the 79's used one of 2 alternators Bosch or SEV Marschall. Odds are it is a Bosch."

Bosch stopped supplying 911 alternators in about '73 (55 amp) and began again in '89 on the 964.
The best 911 alternator was the Marchel 70 amp ('77 - '81) which was an external regulated one.

cobalt

I guess my memory is going.

Looking into my records my second '79 SC had the Bosch unit. For some reason I recall rebuilding the unit on my first '79 SC but it was actually on a '71E I helped restored back in '79. I believe the unit in my turbo is also a Bosch. Guess that is why I expected it to be a Bosch unit.

The engine was modified in Germany back in '84 right before I purchased it. It started out as a 79 SC modified with Max Moritz 3.2L P/C using a Carrera crank, modified european fuel head and other stuff. I know they used the larger fan from the older cars for additional cooling. I guess they used the older alternator when they switched housings.

IIRC both units had similar problems.

VA911

ok more news.
my alternator is apparantly a motorola? is this true?
more importantly i got it back this afternoon and installed it.. guess what?? charge light on!!!!! tested voltage at the batery @ 3000rpm.. 12.04V. tested at the wires at the external regulator. 11.]81V@!!!
its going back tomorrow to find out what went wrong! oh yeah i also pulled it out to check i conected it properly and yeah all good!!!!!! Could have rebuilt half a car in the time this has taken and still no joy!!!!!

Lorenfb

"my alternator is apparantly a motorola? is this true?"

Not unless it's the wrong alt., i.e. the one with the red plate (55amp) and not the correct one (70 amp).

cobalt

If you read the Chiltons manual on these cars they claim the car came with a Motorola unit yet show the SEV unit in the picture as a Motorola.

Wasn't SEV Marchel owned by Motorola at one point?

VA911

it has a green plate.

mark1963911

Red Light On: Replaced battery, alternator and regulator except for the part that plugs onto the regulator and the alternator wires. Any idea if this would cause the red light? Thats the only thing not changed. The alternator is sending a charge to the battery but when its connected through the regulator its to high or too low. Could the switch be the answer? What is this switch anyhow?

Thanks