Particulars:

Engine is a '73.5 2.4L going into a conversion.

The question is the electrical hookup. Did Porsche eliminate the 3 prong alternator plug on this engine and run everything thru the 14 pin engine harness connector?

I've looked and looked and cannot find the alternator connector on the engine harness. The '77 CIS harness I have has the plug near the CDI connector.

It is being put into a '70 914/4 chassis. I have the original relay board and a 914/6 relay board. I'm sick of staring (with a magnifying glass) at three different wiring diagrams (914/4, 914/6 & 911 CIS).


Aaaaaarrrrrrrgggggghhhhhhh!!!!!

This engine should have the wiring for the regulator, unless the alternator was replaced with a much newer one, which have an internal regulator. Either way
wiring does not goe thru engine wiring multipin connector. Make sure the alternator
wires are attached on the back. Dimitri

Thanks, looks like I'm gonna drop the engine and investigate. Need to determine if alt is internally regulated.

Conversions are a pain in the ass!!!!

Either way, you should have a harnes for the alt.

If the alternator has an external voltage regulator, there is a seperate harness for the alternator. If it is internallly regulated its incorporated into the engine harness.

could be a transition year, or a DAPO situation

I don't believe internally regulated alternators were fitted until the SC or even later. Certainly, the 2.7s I've seen had an external regulator. I'm in the middle of fitting a later internally regulated alternator to a '75 2.7. It's not difficult to do, you just have to notch the cone that bolts onto the end of the alternator, or swap it out for a later cone.

The harness for the alternator was also part of the main engine harness for the '75, btw. I don't remember now if there was a three-prong connector on it or not, but I can check when I get home.

Thanks for the replies.....it's just driving me nutz. I don't know if the DAPO changed to internally regulated or not. The engine harness doesn't show any signs of being modified.

Take off the fan shroud and feel the bottom of the alternator "cone". If it's smooth, then it's likely externally regulated. If there's a big blocky thing there, that's the regulator, and it's internal.

Found the Tech Bulletin on The Bird for replacing External with Internal ('74 - '83 911T). Change was effective with the 82 model year. Couple of parts, clip one wire & remove the alt harness at the board, plug back in. I have my fingers crossed, but it still requires checking the cone of the alt to be sure. If the retro fit is done to an earlier car / engine, it requires the 930 fan housing

Or you just take a grinder to your fan housing to make the necessary clearance.