911SC Alternator Update
 

A little help please...I'm so close.
I updated the alternator on my 1980 911 SC last weekend to a Valeo model from Pelican. I read the Porsche bulletin on this process and all went well except for one item - the old voltage regulator. I removed the old regulator and alternator and I took it to my mechanic to check it out... he sent it to another shop and long story short they can't seem to find them now. So since it was the original I thought for the amount of work it was to get it out I would just replace the whole deal. So my issue is what to do with the old three female wire harness that the regulator was attached to? The Porsche bulletin says to "fasten the multi-pin plug of the removed regulator on wire harness". Problem is I don't have that little wired plug anymore since it was attached to the old regulator. I have not hooked up the battery yet because I don't want to fry anything before I figure this out.
Anyone have some advice on this one? BTW the three wire harness female plugs are marked (DF=black wire), (D+=Blue wire), (D-=brown wire).
Thank-you for your help!

I take it that you replaced the externally-regulated alternator with an internally-regulated alternator? And in that process removed the three pin female connector from the bottom of the regulator and removed the now-unneeded regulator. And now you are now wondering what to do the the female connector just hanging around the left side of your engine compartment?

The wires in the connector are still "hot" so you must prevent them from grounding against something. An appropriate dieelectric covering, taped or tie-wrapped in place, would do that job.

So, no connections to this left over plug?
 

Thank-you Brian for your input.

So, I assume from your response that these three wires in the female plug of the harness no longer serve any purpose with my now internally regulated alternator?

The old ones that were not cut off just hang in the engine compartment. No value but cap them off as Brian says. "Fasten to the wiring harness" just means use zip ties or the like to keep it from flopping around. You can double or triple fold the lines over themselves to keep them out of harms way.

Okay, now that we are on this discussion. What should one do with just the opposite situation?

Say you have a 1978 3.0L (with external VR) engine that you want to install into say a newer (1983) 911SC, would I need to find an external VR?

Thanks in advance for help with this request for backward compatibility.

Yes, unless you change out the Alternator to an internal type. the engine wiring harness that should be with the '78 will have the correct connector available for the $50 VR.

Integrated Voltage Regulator.......
 

Ed,

You need an alternator with integrated VR and re-wire the connection to the harness. There is a bulletin from Porsche that explains the simple wiring connection. I did convert my '78 to one with integrated VR in the mid 90's and very satisfied with the result.

Tony

Dennis and Tony:

Thanks so much for these replies to my question!

I do have the harness which came with the 78 spec 3.0L, as well as a spare harness for the 83 spec 3.0L. I had noticed the "extra" plug with the 78 engine's harness. In my case, I did not want to spend the money on a newer alternator (internal VR) until absolutely necessary, and will only be utilizing the 78 spec 3.0L motor while the 83 spec 3.0L is being rebuilt.

In other words, what I am trying to accomplish is keeping my car on the road while the original 83 engine is out and being rebuilt. Maximizing my driving enjoyment in the process, and taking my time with the resealing/rebuilding of the original motor for the car.

Tony, would you happen to have the link to the Porsche bulletin you could share with me?

Porsche bulletin.......
 

Ed,

I don't have any link. What I have is a copy of the technical bulletin Porsche issued for doing the conversion. I'll have the bulletin scanned and forward it to you. Please PM me your email. Or I could mail a copy of the bulletin to you which I have several extra copies available.

Tony

Here's a link to the bulletin that I found. Post #3
http://forums.pelicanparts.com/porsche-911-technical-forum/54271-alternator-update.html

Couldn't you take the whole fan assembly (fan, housing & alt) off the 83 motor and install it on the 78 motor and not have to modify anything?

Wiring connections........
 

The '78 has a different wiring connections for the alternator with integrated VR. That's the reason Porsche came out with this bulletin to guide and help for the conversion.

Tony

Saved by the bell.......
 

Dennis,

Thanks for posting the link. I was about to mail a copy to Ed and saw your post on my way out. I'll PM Ed about this bulletin.

Tony

The way I read it, he's trying to to put a motor that originally had an external VR into a car with an internal VR. So, couldn't he take the whole fan assembly with the internal VR alternator an use it on the '78 motor. Then there would be no wiring issues. No?

That is true, I was assuming he was sending everything out for a rebuild or had some other reason he wasn't wanting to swap the fan and alternator as well as do the wiring modification to the '78 engine harness for the later alternator.
Just add a VR to the '78 wiring harness and good to go!(easier than swapping out the alt assembly)
May want to build and paint/polish his other engine as a complete plug and play so he only has to do a drop and swap when the time comes?

Does anyone have the part number for the protective rubber dust cap on the one wire for the back of the alternator. Mine has cracked due to age?