Alternator Upgrade

[futuresoptions]

Hey guys,

Sorry to bother you with this, but I have tried to search for Early S Man's thread on this subject to no avail. I have a 1977 911s and have removed from the car a marchal 712 237 02 alternator. I have no idea how to post photos in this new setup, but I was able to find this alternator in a post and it was said to be internally regulated. I am installing a later model Bosch alternator al4oox which I believe is internally regulated. I will have to machine my fan housing to make the new alternator fit. What I am wondering about is the wiring configuration. Can anyone send me in the right direction. I noticed that the Marchal had 2 red wires (One thick and one thin) going to B+ which was located at the 6 o'clock position, a thin green wire at the 9 o'clock position, a ground strap at 10 o'clock, a thin blue wire going to a spade clip at 12 o'clock and and 2-3 thin orange wires going to a post marked D. I know its hard to tell without photos.... The New Bosch has three post on the back one on the B+ side and two on the side marked D-. Any suggestions would be appreciated.

Thanks

[futuresoptions]

I have decided to just keep the original type alternator. Will post the Bosch unit for sale next week. part# 911 603-120-04 Bosch rebuilt#AL400X will come with nut and pulley half.

Thanks

[boyt911sc]

Future,

I have a copy of the Porsche Technical Bulletin regarding converting an alternator with external voltage regulator to one with integrated VR. Contact me at atd911@hotmail.com and I'll forward to you a copy of the instruction. Good luck.

Tony

[futuresoptions]

Thanks Tony,


I finally found that post with the technical bulletin, but I figured out that my Marchal is externally regulated.... I figured that if I machined my housing that it would probably make it weaker and I would rather not fool with trying to locate the correct later model housing. I will just have my alternator rebuilt and purchase a second used alternator as a spare.

Thanks

[911 envy]

Originally Posted by boyt911sc

Future,

I have a copy of the Porsche Technical Bulletin regarding converting an alternator with external voltage regulator to one with integrated VR. Contact me at atd911@hotmail.com and I'll forward to you a copy of the instruction. Good luck.

Tony

Tony I’m replacing alternator with Bosch unit with built in regulator. I can’t locate the bulletin you are referring to. Can’t determine your email address. My email is rplantz217@gmail.com

Thanks for your help.

[wazzz]

Check your email. Just sent you a link for the TSB series, in which you'll find the required bulletins. It is a big PDF, about 50MB.

[kgieg]

Originally Posted by wazzz

Check your email. Just sent you a link for the TSB series, in which you'll find the required bulletins. It is a big PDF, about 50MB.

What is the TSB series? Is it a group of factory bulletins?

[wazzz]

Originally Posted by kgieg

What is the TSB series? Is it a group of factory bulletins?

Yes. And there are quite a few of them. The PDF file contains 562 pages.

[Jonny H]

We have the Porsche bulletin as part of our 175A alternator install manual.

See here: https://classic-retrofit.com/forum/index.php?/topic/1204-175a-upgraded-alternator-installation-manual/

[pmax]

Originally Posted by futuresoptions

Hey guys,

Sorry to bother you with this, but I have tried to search for Early S Man's thread on this subject to no avail. I have a 1977 911s and have removed from the car a marchal 712 237 02 alternator. I have no idea how to post photos in this new setup, but I was able to find this alternator in a post and it was said to be internally regulated. I am installing a later model Bosch alternator al4oox which I believe is internally regulated. I will have to machine my fan housing to make the new alternator fit. What I am wondering about is the wiring configuration. Can anyone send me in the right direction. I noticed that the Marchal had 2 red wires (One thick and one thin) going to B+ which was located at the 6 o'clock position, a thin green wire at the 9 o'clock position, a ground strap at 10 o'clock, a thin blue wire going to a spade clip at 12 o'clock and and 2-3 thin orange wires going to a post marked D. I know its hard to tell without photos.... The New Bosch has three post on the back one on the B+ side and two on the side marked D-. Any suggestions would be appreciated.

Thanks

[mysocal911]

Originally Posted by futuresoptions

Thanks Tony,


I finally found that post with the technical bulletin, but I figured out that my Marchal is externally regulated.... I figured that if I machined my housing that it would probably make it weaker and I would rather not fool with trying to locate the correct later model housing. I will just have my alternator rebuilt and purchase a second used alternator as a spare.

Thanks

Best choice for your year 911!