Alternator change

[schmaz356]

I have a 1973 914 that I will be installing a 3.0 from a 78 SC. I will be deleting the regulator plate as I don’t need it for the EFI that will be installed. I also have a new Paris Rhône 90A alternator from a 1984 Carrera. The part number is 911 603 120 05. I believe this has an internal regulator. Will this alternator fit with the SC shroud and should it work. Again I’ve had the alternator for several years however it had not been in a car. At the current prices, I’d hate to not be able to use this unit.

[timmy2]

Should fit ok, but you may need a new cup washer and nut for the different shaft.
Air deflector on the alternator will likely need modifying as well.

[al lkosmal]

Another thing to consider with the change from external to internal regulator style alternators........a resistor needs to be installed to ensure that alternator excitation occurs. The resistor assembly referred to on the bulleting is NLA, but I just buy the resistors online and make them for myself





regards,
al

[clarkd]

This chart shows fan shroud dimensions by year.

[eastbay]

I put the 90A Carrera alternator and matching air diverter in my 74 with no fitment issues at all and did not need the resistor. As mentioned, you need the correct size pulley hardware.

The matching air diverter is still available new, which is what I used.

edit: I used the matching "930.x.x.x" Carrera fan shroud, fan, etc. and just dropped in the entire alternator/fan assembly, easiest way to go.

[HaroldMHedge]

Sorry Dennis (timmy2), I disagree with you about mounting the 95 amp alternator into the 78 3.0L fan shroud. The chart posted by clarkd indicates that the 78-79 shroud depth is 95 mm and the 84-89 shrouds have a 106 mm depth. Doing this install the pulleys would not line up correctly.

Edit
This is my 911 post.

[pkabush]

Originally Posted by HaroldMHedge

Sorry Dennis (timmy2), I disagree with you about mounting the 95 amp alternator into the 78 3.0L fan shroud. The chart posted by clarkd indicates that the 78-79 shroud depth is 95 mm and the 84-89 shrouds have a 106 mm depth. Doing this install the pulleys would not line up correctly.

Edit
This is my 911 post.

I ran into this on my 81 930
I believe this can be overcome by machining 13mm out of the mating surface on the inside of the fan housing. In my case I just went back to my stock alternator
However, if I ever decide to go with retro electric A/C I’ll look into having my housing machined to accept the larger alternator.

[timmy2]

Originally Posted by HaroldMHedge

Sorry Dennis (timmy2), I disagree with you about mounting the 95 amp alternator into the 78 3.0L fan shroud. The chart posted by clarkd indicates that the 78-79 shroud depth is 95 mm and the 84-89 shrouds have a 106 mm depth. Doing this install the pulleys would not line up correctly.

Edit
This is my 911 post.

Yeah, didn’t notice it was a 78.

[timmy2]

Originally Posted by pkabush

I ran into this on my 81 930
I believe this can be overcome by machining 13mm out of the mating surface on the inside of the fan housing. In my case I just went back to my stock alternator
However, if I ever decide to go with retro electric A/C I’ll look into having my housing machined to accept the larger alternator.

The CR alternator needs a spacer added for later year cars. It is designed to be a direct fit for the earlier thicker housings. (So it is “smaller”)
I had to add one for my car installing the WOSP unit.