Generator Help!

abrokenframe · 03-05-2012, 08:26 PM

Hello everybody,

So I've owned a 1968 Porsche 912 for a week now. When purchased, the generator light would stay on at idle and turn off at higher RPM's. That was until two days ago. The light now stays on at all RPM's. The car now needs a jump to start and all electronics are dull since.

I started checking out the voltage regulator and generator. First off, my engine has been replaced with what I'm guessing is a '67 by the serial number: 753624. However, the generator is a 7volt (part #: 0-101-206-029) which I think is from a 356.

I replaced the 14v30a regulator with a 14v25a considering the generator was not correct to begin with. I still have the electrical issue, which leaves the generator. So I'm trying to figure out which direction to go with the generator. Do you think I should rebuild the 7volt, buy the brand new replacement found on Pelican Parts, or search for an original 67 or 68 generator? Also, how does this effect which regulator I am using?

Thanks for any help guys. I'm learning.

JT912 · 03-06-2012, 06:27 AM

7V? I know some (all?) 356's were 6V and 912's are 12V. Not certain how that relates to what you are listing. The early 912's did use a smaller diameter generator than later.
Googling the part number and it comes back as an early ('56-'59) 6 volt 356 generator. This in combination with a possible incorrect regulator might be part of your problem.

WFBowen · WFBowen's Garage

I think you first need to check the generator for output (if any) and work from there. Your generator might have been rewound to 12v which wasn't uncommon in the late 60's when lots of 6v cars were upgraded to 12v systems. As a basic initial test, look at your generator brushes to make sure something's there.
Either way, the best solution is to get a known functioning 12v generator and it's matching regulator so you at least know that those critical parts are working (keep in mind that the Porsche "large" and "small" diameter generators use different regulators, fan backing plates, mounting stands, etc.) Then you can work your way forward to check for good grounds, etc.

abrokenframe · 03-06-2012, 03:11 PM

JT912, you are correct, it is a 6V. The funny thing is the casing on my gen says 7V. I researched it and that is normal. The system with the 14v30a was working for a while, but the generator is making this sound that I don't remember...

The voltage regulator I replaced is the 14v30a that came with the car (I’m assuming), but didn’t match the lower powered generator that came with the replaced engine. That’s why I replaced it with the 14v25a, which I think was used on pre-68’s.

WFBowen, I would have never even thought that they rewound these! I'll have to check that out because that makes everything make more sense. I did check the brushes and they were still functioning, but prob needs new ones anyways. I was leaning towards buying the brand new generator found on here, but am worried about the conversion sizes considering I have the smaller casing and I think it's larger.

I'll let you know what I find and thanks for the help so far.

abrokenframe · 03-06-2012, 04:16 PM

The generator is not reading on d+/61, so I am removing it.

Jaems Thomsen · 03-07-2012, 09:33 AM

Parts Obsolete was selling a Alternate conversion kit for the 912/356. It included the stand so it was a complete kit. It was not cheap.

abrokenframe · 03-07-2012, 04:38 PM

Dang that looks clean. I went to their website and couldn't find that kit though. I think I'm going to rebuild the one I have and see how it does. I just need to find a good, reasonably priced shop to rebuild it in Southern California. Can anyone recommend a place?

Scott Douglas · Scott Douglas's Garage

I'd send it here:
AutoLectrics, Campbell, CA, (408) 559-3540
The best rebuilder / repair facility for your starter or generator.
I went with the alternator kit on my old sunroof coupe.

abrokenframe · 03-07-2012, 09:04 PM

How do you guys like those kits? I really haven't seen too much about them. They look like they could power two 912's each...The black is sweet. Seeing a black 912 is what turned me on to them.

Funny you mention AutoLectrics because I heard about that place from this website:
Generator.

I was hoping there was somebody closer, but I'm realizing its probably worth it just to ship it out there.

abrokenframe · 03-17-2012, 04:11 PM

So I shipped it out to Autolectrics and they said that the 6v was never rewound to a 12v. That prob explains a lot of my electrical issues. Should I be checking any other electrical parts in the car before putting the 12v in (besides the VR)?

Jaems Thomsen · 03-18-2012, 08:29 AM

Check all your bulbs, flasher, and etc. to make sure that they are still 12v and not 6v.

WFBowen · WFBowen's Garage

This is the first time I've heard of someone throwing a 6v generator into a 12v system. The opposite (12v into 6v system) was common where you'd just change the bulbs,radio, etc. and live with hyperspeed wipers and starter motor. My only suggestion would be: After installing the new generator, start and run the car with all of the accessory fuses out. Once you've established that the starting/charging/ignition are functioning, connect the fuses one by one to make sure those circuits are short-free.
Good luck,
Bill

abrokenframe · 03-19-2012, 03:20 PM

Yea that's some good advice, I'll definitely do that. It doesn't make sense for the previous owner to change everything for one part...and it was previously using a 14v30a regulator. The ignition coil blatantly says 12v as well.

Autolectrics claims that the armature and everything was original and 6v. Maybe it was manufactured as a 12v in a 6v case and it was too far gone for Autolectrics to really test it so they made the assumption?? I don't know, those guys are said to be experts and I am not. I just don't see how the car would be functioning with 12v parts if it wasn't a 12v generator.

WFBowen · WFBowen's Garage

I don't know how well you knew the previous owner, so i'll tip-toe around this subject by saying that any car can run for a while off of a fully charged battery. There might be a possibility that the PO merely installed the wrong generator before selling the car, but guys who have 912 12v and 356 A/B 6v generators laying around their garages usually know what they're doing. I'm no electrical expert, so I don't know if a 6v generator running through a 12v regulator can get any charge at all to the battery.
As for the guys at Autolectrics, they've been around a while and I'd definitely respect their opinions. Are they going to set you up with a 12v generator?
Bill

abrokenframe · 03-19-2012, 08:31 PM

A little background: The owner did not know the car very well. He purchased it from his boss about 4 or 5 years ago. His boss was the second owner since the early 80's. The engine was blown in 2001 by an extreme red line so they replaced the engine. I have what I believe to be all of the maintenance records dating back to 1976. Only about 1,600 miles have been put on the 912 since the engine was replaced. According to my records, nothing was changed since the engine was added and there were no records of a 12v to 6v conversion. I don't think the PO would have also taken the time to replace the generator himself, nor did he drive it enough to really know what was going on with it. It has mainly been sitting for a while.

This leads me to believe either the engine they purchased was planned for a 356 maybe (even though its a '76) and the mechanic did not realize the generator wasn't 12v; or Autolectrics is wrong. I highly doubt that mechanic or the PO switched any of the electrical for a 6v.

The generator seemed to be working for the first week that I drove it, though there were random electrical issues such as the radio not turning on all the time or one headlight going out and dull lights all around, needing a jump here and there, etc. Eventually, the red light stayed on no matter what RPM I was at.

Autolectrics basically replaced everything (armature, pads, etc.) to work with a 12v25A system.