Late alternator for my 67S

[silveranger]

Can anyone out there give me some direction on wiring up the late internal regulator type alternator to my 67 wire harness? Any help will be appreciated.
Thanks
John

[304065]

You don't want to do this.

A 67S has a 250mm fan and the electrical system was designed for a 35A Bosch Alternator with the VR on the electrical console.

Using an internally regulated alternator requires the use of a later fan shroud because the bigger alternators are longer. All these later fan shrouds are 245mm (with the exception of the small SC for a couple years). This will require a later fan also.

$800 later, you will have a huge alternator capable of feeding 90 amps through the teeny little wire to the electrical console. They didn't even use a big wire to the starter terminal like the LWB cars did. So you would have to add that on, but even the wire running forward to the battery is smaller than in later years.

HEAT is the enemy of electrical components and the VR is no exception. Locating it three inches from the top of the engine, so that when the engine is off and the fan isn't running, subjects the VR to massive heat soak that will destroy it in a fairly short time. This is one of the reasons for the lousy performance of the later alternators. Another failure mode is when it heats up it stops working, causing you to immediately pull over because the "G" light is on. For most Porsche owners, the "G" light doesn't occasion concern for the battery or the charging system, it means THE FAN BELT HAS PARTED AND THE ENGINE IS ABOUT TO SEIZE.

Anyway, if your charging system needs work the best thing to do is fix it, the parts are available new. If you post the issues you are having I'd be happy to steer you in the right direction.

[silveranger]

Hi John,
Thanks very much for your input. You have brought up some issues that, of course, hadn't ocurred to me. I think i'm going to have to rethink my installation.
Thanks again,
John