Alternator Shield

[Bob Kontak]

Originally Posted by gamin

Len 911 - Yes, you need the ground wire.

You definitely need the fat brown ground wire from the alt to the case. Not sure about the wire that attaches to the two studs on the outside of the fan housing (2nd pic is post #4).

[The cap'n]

Originally Posted by Bob Kontak

You definitely need the fat brown ground wire from the alt to the case. Not sure about the wire that attaches to the two studs on the outside of the fan housing (2nd pic is post #4).

It should be obvious from the non-standard low buck insulated crimp connectors that the extra ground wire has been added by some hack, for whatever reason.

The Cap'n

[Bob Kontak]

Originally Posted by The cap'n

It should be obvious from the non-standard low buck insulated crimp connectors that the extra ground wire has been added by some hack, for whatever reason.

It is obvious, but from reading Len's question, he asked if he needed this (DIY) ground wire. The response was "Yes, you do" I wanted to clarify between the two wires. Brown, yes and the other, I did not know what it's for.

[R_Builder]

Porsche doesn't generally throw something in a design without a good reason (or two). The air guide on the back of the alternator helps force more air to the #1 and #2 cylinders since the fan's CW rotation tends to throw most of the air towards the 4/5/6 side. The oil cooler has its own super-nice duct in the shroud to force feed it. Its pretty much that simple, but...

Between alternator swaps, different alternator types (built in VR versus separate), and a general lack of good access in there, all sorts of wierd things happen over time for the sake of getting the job done quicker. Get the correct air guide, hook up a direct ground to the case, and make sure your fan belt runs straight down to the drive pulley on the crank. Any angle to the belt when looked at from the side of the engine means you have the wrong altenator or the install didn't quite go right.

As you might guess, I have inherited more than one messy install in this area from previous owners .

Hope that helps,

[wwest]

Originally Posted by mysocal911

"I had the impression that it was less a shield than an airflow "guide" to help cool the alternator."

"I suspected the cylinder #1 cooling answer based on the photos"

Both logical, as more than one purpose.

+++

[Pato911]

So, on your advice I ordered a new one and it arrived today (it is very nice and well made). The problem is that it appears to be incorrect although it is the part number from the Porsche parts catalog (same as in OP).

The cutout is on top and seems to be for the VR but is ~1/4in to short as are the slots for the studs. I am debating whether to return it or modify with a dremel (I lean towards modify as I am impatient).

Some pics with the original alternator (successfully replaced with one from Ebay (Eagle Elec))

[Len 911]

You have to install the alternator first in the housing, that will make up fot the 1/4" ..then put the new air diverter on. you should be ok if not dremel that baby

[Pato911]

Doh!

[Len 911]

Hey We all have those moments.. I just happen to have more thean most

[RSTarga]

That cutout is for the internal VR , it should match up with your alternator. Maybe they went to a top mounted VR .

[Speed Buggy]

Hi gents, I replaced my alternator a couple of years ago and there was no shield. I have an '81 SC with a 3.0L that I just rebuilt. In going back together I broke the housing and I need to order a new one. My question is does my '81 use the shield / extension? I've read somewhere that the older cars do use it but the alternator has to be rotated.Thanks.

[The cap'n]

Yes. Be sure to get the correct one.

The Cap'n