SharkSkin

I figured a true "rain expert" would be along soon Another vote for "Put the belly pan back on"?

SharkSkin

Well, I have the alternator and picked up a cooling shroud. It's going to be interesting trying to adapt the shroud to the alternator.... off to the garage for a little head-scratching...

SharkSkin

I'm not so sure anymore that modifying the original shroud is the best way to go. I'm concerned that if I trim it to fit then try to bolt it into place, it will end up cracking. The original part has reinforcing ribs around all the attachment points, and even so they are known to crack.

Does anyone know exactly what kind of plastic it's made of, and what would be the best glue/epoxy to use on it?

I'm off to pick up parts for plan B, which involves a 2" copper elbow that can be bolted firmly to the alternator and a plastic "sub-shroud" to direct cool air around the vicinity of the B+ terminal. I'd be tempted to form the whole shroud from copper since it's so easy to form & solder, except that I'd be worried about it shorting against the B+ terminal. The design of this unit does not require a shroud that covers the entire back end of the alternator, since there are only two small inlets that are likely to pick up hot air from the vicinity of the manifold.

The pics below help illustrate. The rear view is approximately the correct on-car orientation(Just rotate it another 20° or so clockwise). The unit that I had built has the rear cover rotated 90° CW compared to the pic below, and I only have one of the two threaded mounting bosses shown at the 7 & 8 o'clock positions in the pic; the 8:00 boss is not present on my unit.

The air intakes I'm worried about are at two locations on the rear plastic cover. One is on the side adjacent to the connector, at the regulator, and the other is comprised of the three holes on the back, one of which is partially occupied by the B+ terminal. There is a third air intake(that I'm not worried about) on the face behind the pulley, and the outlets for each of the two internal fans are the large slots closest to where the case splits. I was wrong in my earlier assumption that air is pulled all the way through the alternator, back to front. So anyway, if I rigidly mount a 2" copper ell to the threaded boss, direct half of the air over the regulator, direct the other half out to the intake over the diodes, I should be good to go. The last pic is a very rough photoshop that illustrates how my alternator is "clocked", the (approximate) expected orientation when mounted, and the area where I want to distribute cooling air. The circle represents the forward-facing connection for the flex tube

I didn't worry about this too much before, since I always knew that my alternator was barely adequate and I would someday replace it with the best alternative I could find. I know there are plenty of people who don't care about any sort of cooling shroud, but now that I'm in there spending money I want to do what I can to keep hot air off the exhaust manifold from getting sucked into the alternator.

Any insights on the glue question above are welcome, as I am not quite ready to completely abandon that approach.

heinrich

Dave I'd take some thin aluminium and just make a 1/2- covering lower cover for it, bolt it to the front.

SharkSkin

H, not sure what you're getting at. Cool air needs to get in through the plastic back cover or there's just no point.

heinrich

Any air will be fine. So make a big fat half-nutshell and bolt it on.

SharkSkin

I disagree. If the outlet slots on the side of the alternator are in the same "plenum" area as the inlets in the black plastic cover, then air will just get pumped around in circles, getting progressively hotter. Maybe I wasn't clear about how it's set up. See attached pic for airflow details; Blue is intake, red is outlet. Regulator and diodes are the most heat-sensitive components.

Garth S

The Paris-Rhone alt. cover on my '80 is formed of steel vs the plastic you mention. If the plastic is a reasonable fit ( with mods), perhaps locating a metal one will save some effort???

Airflite40

Dave, Im planning on doing this mod too as soon as you finish, since your other write ups are very well written and detailed. Are you going to chage the pulley to the old one? Borys.

BC

That one looks nice and light.

Andrew Schauer

Dave A.-
I've got a Paris-Rhone alternator shroud you can have for your project if you think it would work with some modification. Let me know if you're interested.
PS- I can send pictures if need be also.

Tom. M

I had comtemplated doing the delco conversion after my alt failed on the way back from SF05...but I was browsing ebay and came across a rebuilder (Eagle auto) that listed a 130 amp rebuilt alternator (for GTS) for a BIN of 109. Could have just rebuilt mine..but at that price I figured it was worth trying. Got it and installed it last week. Works perfectly. The volt meter actually shows near 14 volts...a place its never been before . Here's a link to his store... http://stores.ebay.com/EAGLE-ELECTRIC .

Not saying that everything he sells is good..but the one he sent me works fine.

BTW...while searching..I ran across a rebuilt alt being sold by J Serio...don't know if that one is still available...but it was listed at a really good price too...

Later,
Tom
89GT

P.S. Pics of my 172k mile alt (likely original) and very worn brushes are onthe pacnw yahoo page for those intersted. Alt tested fine but one of the brushes was worn so far it was making only intermittant contact with the rotor.

Bill Ball

So, the one he indicates is for 92-95 928 fits MY89 without any modification? [Edit: OK, I see elsewhere it is the same for 85-95]

BC

Can you guys weigh the Delco unit? I have the 85 and later alternator on the shelf and I would like to compare.

SharkSkin

Andrew, Garth, I'd love to see a pic of the Paris-Rhone or other metal shroud. I'd still be worried about clearing the B+ terminal because it's metal. Also, I have a feeling it won't be "deep" enough to engage with the case bolts on the Delco unit.

Borys, those pix are off the net -- the unit I bought has the single vee pulley, but they threw in a double-vee and a ribbed pulley so I could eventually post the info needed to determine if this can work for all shark applications. They also threw in a few of the different size spacers that are available to go behind the pulley for fine-tuning offset.

Brendan, it weighs right about 11-1/4 pounds. I'm sure the "lightness" is relative... do you have any loose alternators you can weigh?[Edit]I posted before I saw your last post...[/Edit] Naturally I'll weigh mine when it comes out.

Tom, does the needle ever "jump" when charging? My understanding is the Delco unit offers much finer control over voltage than older designs -- IOW if you add additional load, The Delco will smoothly adjust to give exactly the power needed, while many other regulators have sort of "stepped" output so will tend to charge a hair over or under what's needed if circumstances fall between the "steps". Could just be Delco hype though.

Note that the Delco 105A unit would have run about $100. Biggest downside I can see to using the 130D series is the hassle with the shroud.