gregg911

My alternator makes noise like the bearing is going out. Anyone remove, rebuild and replace the alternator in an SC and can give me a heads up as to what is involved?

1980 911SC

Bill Gregory

If you're going to rebuild, that's one thing. If you're going to buy new, then there is additional work involved. Porsche changed to an internal regulator in 1982, and the 82+ alternator is what's available for earlier models. Not a big deal - there's a dealer bulletin on the process, entitled, 'new alternator has integrated regulator'. If you have the Porsche Parts and Technical Reference Catalog, 74-89, it's also printed as technical bulletin 1. There are a couple of articles on the 'net detailing alternator removal. Actually, if you do your own work, you should have a copy of the Bentley 911SC Maintenance Manual, around $75 on the internet (full disclosure note, I helped edit the second printing). Beats $350 for the Factory Manuals.

john d 81SC

gregg,

Mine went bad at a DE at Watkins Glen. Luckily a friend trailered my car back home for me. I looked at the options, and decided on a new alternator from Vertex (Vallejo) since mine was cooked and a rebuild was out of the question. Only adjustment was cutting out the fan shroud with a hacksaw to accomodate the integrated regulator (easily done). Vertex sent me a wiring diagram, and installation was easy. Just make sure they send you the correct 'washer' to fit the new shaft - not the same size as the original (at least on an SC).

CDiercks

If you can, have it rebuilt. At least that is my opinion. Everything I have read and heard is that the external regulated alternators are more reliable. I had mine rebuilt while my engine was out, and replaced my external regulator just in case. It's not hard to remove, and I have the piece of mind that I will probably never have to mess with it again.

Do a search and you will learn a lot about the different alternators Porsche used, and which are to be avoided.

r911

"Everything I have read and heard is that the external regulated alternators are more reliable"

_ but what is that? I have nothing except loren's opinion. He may be right, but I have seen absolutely no data. A newer alt. will have less usage on the elec. components and newer, improved versions might be in the newer alt. "might"
The ext. VR cars are easier to get to when the VR goes out.

So I think you can go either way - it is probably cheaper to rebuild and that may be the deciding criterion.

CDiercks

Everything I have read and heard consists of the research I did on Pelican, speaking to a well known Porsche mechanic, and the person who rebuilt my alternator. Yes, no hard data there, but it was plenty to convince me to rebuild it as opposed to replacing it with an inferior (IMO) alternator at twice the price.

RoninLB

afaik the internal regulator is fine at 210deg. At 220-230deg it's a maybe.

Paul Conquest

I did the bearings on mine this spring. Getting the alternator out is a finicky job, but not technically difficult. There is a good how-to on the Pelican site at http://www.pelicanparts.com/techarti...lt_replace.htm . The most difficulty was encountered in getting the 6 small nuts that hold a veined, fiberglass shroud onto the back of the alternator off, as the combination of tight quarters and orientation of the veins makes it hard to get wrenches and fingers where you need them. When you get the shroud off, make yourself a drawing of the wiring BEFORE you disconnect anything.

As for the rebuild part, you might need a puller to get the old bearings off the alternator shaft. I purchased a cheap ($10) puller and then ground and reshaped the arms to fit the purpose. Once you get the old bearings off, take them to your local commercial bearing supplier and you can purchase the replacements for about $25. If you need brushes, you can probably get them made locally as well. Although I didn't need brushes, a while back I found a local supplier who does nothing but industrial brushes and he usually charges about $20 for custom fitting a pair.

Excluding travel to the bearing supplier and tool store, it took me about two hours time to do the entire job ... and things are oh, so quiet now!

DGaunt

It is only common sense that the internal regulator is in a really hot spot, esp. when a hot engine is shut down, eliminating the air flow over it. I suspect Prshce went internal because it was cheaper, not better.

r911

Maybe it was for cheapness. But I have not seen any data on the thermal tolerance of the devices used in early ext. regs or in later int. ones. Generally, the tolerance to heat for such devices has gone up over time.
Nor have I seen failure rate data...

If it were me, I'd just rebuild what I had. I swapped engines recently and felt no need to alter the new engine's internal regulator to make it external. I expect to get many years of life out of it.

One thing I'd be interested in would be a light wt. alternator. I hear there is a British firm that makes them. Racers who are doing swaps or rebuilds might want to try and dig that info up somewhere.

RoninLB

I wanted to place a heat strip/ marker on the alternator case for a temp reading but couldn't locate the proper temp strips or marker. IMO that would be great info.

r911

How about a type K thermocouple - many mutlimeters can read them.

I'll do it with a type T tcple next summer if you remind me. I can ue a data logger and record Tair as it cools down after engine shutoff -- one channel for int. VR area, and one for ext VR area.

I'd worry about the stick on coming off and falling in there....

der Mond

I recently installed a new Australian K3 alternator as advertised on the Pelican site on my '87 Carrera. They are available for your car. Check out the main site at:

http://www.k3.com.au/index.php?page_id=3

...and here is a site with additional photos:

http://www.autofarm.co.uk/Parts/K3Alt.html

RoninLB

My very long Fluke probe would be a pia.. although not if I stopped and did it at idle.. Your hard info would be a home run. I'll rememberto remind you for sure.

the "stick' is like a marker pen.

r911

ah.. the crayons - well, that makes more sense than the LCD sticks which are for lower temps.

if thick it might drip off...