jwillman

My 79 came with a Bosch AL115X rebuilt alternator. The car never had the cooling shroud or hose.

I pulled the alternator to clean it up and fix all my oil leaks and decided it was time to put back the alternator air intake system.

The back of the alternator does not have any posts to secure the shroud nor does the PN 928 603 133 04 schroud seem to line up with the open holes on the back case of the alternator.

What PN schroud fits this alternator - if any

What do I use to make the posts I need to mount the schroud should I be able to find one?

soontobered84

Jim,
I think I read somewhere that a replacement alternator for the earlier cars was an alternator that fit a Mercedes. The caveat was that the Mercedes alternator dd not use the shroud.

Is it possible that your alternator was replaced with the Mercedes version of the alternator?

dr bob

The AL-115x is a "universal" replacement from Bosch. In return, the through-bolts that hold the shroud on the 928 need to be swapped from the old alternator. For folks that retrofit this into earlier cars that were oe with Paris-Rhone, these bolts don't exist. The shroud and snorkel are different too. Rebuilders should have the longer screws. Late shroud comes from 928 international, who may also have the screws. They have the correct alternator with correct screws and correct clocking ready to go, to remove all the aggravation.

jwillman

Thanks Dr Bob.

Fogey1

You are not alone.

PLEASE post pix again in this thread when you get this figured out and fixed.

jwillman

I think I will give up on the idea of trying to add the cooling schroud to the AL115X alternator.

Based on the thread and discussions with Roger trying to make a schroud work with this alternator is way to more time and money than I want to invest.

Since it appears I am going to have to accept the performance degradtion from heat issues I am going to switch to the 88 Camaro V6 alternator better known as the AC Delco conversion.

From what I have read here although I may suffer the same heat related performance drop I am starting out with 15 more AMP's and some more modern electronics and idle charging performance for $42 delivered and no core charge.

Thanks All for the input.

WallyP

Jim,

I suggest that you continue to consider installing the cooling shroud and hose, even if you use the Delco alternator. While I have not done this, it would appear to me that it should be possible to retrofit the shroud to the back of the Delco. The fit may not be perfect, but the gains might be substantial.

If you look at the photo at the top of this thread, note the oil and dirt build-up. The 928 alternator lives in a very hostile environment. The "cooling" air is pulled in from almost under the exhaust manifold, after it has gone thru the radiator and AC condenser. This "cooling" air will be around 200 F in the summer - does that help the alternator? In addition, many 928s have minor, but continuing oil leaks from the poser steering system and cam covers. The oil attracts dirt, and eventually the inside of the alternator is coated with an insulating layer.

You might look at making some right-angle brackets from sheet metal that can be mounted to the case screws, and which will then hold the cover. There exists a plethora of methodologies by which a feline may be divested of its hirsute covering...

jwillman

Thanks Wally.

I am currently in the process of replacing all the front side seals for the very issue you point out.

I had engine oil leaking onto the alternator from the camshaft and oil pump seals on that side as well as oil leaks from the other side camshaft and crankshaft seals. The alternator was way uglier befor I cleaned it up a bit.

I had intended on taking the alternator apart for a thorough cleaning as well.

jwillman

When I got home tonight I took another look at the AL115X alternator and the schroud I got.

The four bolts that hold the alternator halves togather have recesses that extend to the back side of the alternator. Those align with the mount point holes in the schroud.

The bolts that hold the halves togather are 2.5 inches long.

I have come up with 3 ideas depending on what hardware I can find:

1. I need a 5 inch long bolt thats threaded the last 3 inches so that it secures the halves togather and the threaded end extends past the back edge to allow me to secure the schroud.

2. cut down the 2.5 inch bolt and get a threaded rod to screw into the open threaded pearch of the alternator now open with the shorter bolt.

3. Get a 3 inch bolt to secure the halves and then thread a female to female adapter onto the exposed end past the alternator housing and attache a threaded rod to that for the schroud mounts.

Thoughts form the forum? Any idea what size the alternator halve bolts are? The look like M6.

Jim Devine

If you need something longer that is threaded, this might work- cut to fit
if the thread pitch is correct.

http://www.fastenal.com/web/products...0A20000&ucst=t

Looks like it's 1 meter long- plenty of room for lots of mistakes

WallyP

The stainless rod looks like a good idea. Take one of your screws to a fastener store (Google is your friend) and get enough rod to make new fasteners that are long enough to go thru the alternator and hold the shroud. Get enough matching nuts to put a nut and lock washer on the front and on the shroud.

Cut the rod to approximate length, leaving some excess for later trimming. Smooth one end. Remove one screw, thread the smooth end of the rod thru the alternator case from the rear until it sticks out the right amount on the front. Nut and lock washer there.

Mount the shroud, mark the rod. Repeat until done.

Cut the rods, round the ends, mount the shroud, being sure to clock the hose correctly.

Tom in Austin

Looks like you're on the right track Jim. I actually have a receipt from the PO where he had the alternator 'boiled out' and new voltage regulator installed, so agree with Wally it can be a tough environment down there. Once you have a cooling solution rigged up it will be one less thing to worry about.

Plus, at least on the late model cars, the air drawn through the alt cooling hose passes over the external temp sensor for the A/C, so conceivably retaining this entire system may help your A/C function better ...

waynestrutt

While on this subject of the cooling duct. The duct directs cool air through the alternator from the back and the fan directs air from the front. So what we have is a stand off,ie no airflow through the alternator. Also with the fan on everyones alternator the vanes are pushing air radially to the front face and not scooping air and forcing it through the alternator body. If the fan was turned around it would scoop air and draw it forward out of the alternator assisted by the pressure from the flow the shroud provides. Anyone have any explanation or other theory?

BRB-83-911SC

I *think* the alternator fan extracts air from the alternator, so airflow with the hose is all same direction. If the fan pushed air into the alternator, I would think it would also pick up and push all of the sand and road debris in as well.

ROG100

It pulls air to the alternator IIRC.
The U in the hose stops ingress of crud