Alternator to Fan Housing flush fit?

getluky · 03-28-2007, 09:35 PM

I've been looking through the forums, read a TON of history about this stuff, and still I would like a final nod that i'm doing things the right way before I proceed.

Without getting too much into the backstory, suffice it to say that i'm trying to get a refurbished alternator back into a fan housing for an 87 3.2 Carrera.

I have both a Vertex aluminum unit that i'm trying to get it into, and the original mag housing which is cracked and possibly warped.

In both cases, it seems like the rim at the lip of the alternator is preventing it from sliding in to the housing slot completely. From reading the forums, some have said that it's a slide in piece, and others say that you must mallet it in until the alternator is completely flush against the housing.

As you can see from the before photo, it was originally flush against the mag housing. It was a pain to remove (this may be a red herring, but two shims were placed in the inside of the pulley, and five outside).

As you can see from the after photo, sliding the alternator in by hand (without mallet-ing) leaves space, and it seems like that lip around the alternator is what stops it.

I've put anti-seize on it, and am mallet-ing with most of the studs removed. I'm trying to avoid getting bent studs like were originally on the unit when I first tried to remove it. I'm not sure if they were my fault, or from the PO.

Can you give me confirmation that the back of the alternator absolutely has to sit flush against the housing slot? If so, this seems like quite a tight fit, mag or aluminum housing aside.

Thanks in advance,

Gordon

cmonref · 03-29-2007, 03:34 AM

getluky,

The position of the end of the alternator where the electrical connections are is not a determining factor in whether the alternator fits properly. This position is what it is when the alternator is in correctly installed.

The alternator is indeed a slip (slide) fit into the alternator housing. But after 20 years, it is not exactly a slip UN-fit -- it does NOT come out easily, as you have found out. Corrosion between the mating surfaces causes this, and breaking the corrosion bond during removal of the alternator can be a pain -- and the cause of bent studs.

If the alternator does not reinstall smoothly, you will have to lightly sand the inner diameter of the mount's mating surface -- that is the surface that is rubbing against the surface that you put antiseize on as shown in your third picture. I used a dremel with a sanding drum and lightly went around and around until the alternator slipped into place.

Don't drive the alternator into place. Sand until it fits.

By the way, the number of spacers inside and outside of the fan belt determines the tightness of the belt. These spacers are not intended to move the belt slightly inward or outward to make up for an alternator that does not fit correctly in the mount.

Good luck.

Brian

getluky · 03-29-2007, 08:24 AM

Thanks Brian, i'll take my time with a dremel and try to be patient.

cmonref · 03-29-2007, 09:43 AM

Another thing -- if you have the Vertex aluminum fan shroud, test fit it onto the engine. On mine, the curvature of the radius above the crankshaft pulley was not correct, and the slot on the bottom of the fan shroud that fits over the locator pin on the case needed a little work, so the trusty dremel got more use. Others have remarked that the capscrew holes in the top of the fan shroud did not match up exactly with the holes in the fiberglas surround.

getluky · 03-29-2007, 10:00 AM

Thanks, I tried out a test fitting first thing after I got the piece. It didn't fit exactly correctly, as I had to use a flathead screwdriver and a bit of patience to pry the fiberglass fan shroud up a bit to let the right-side mounting post to get underneath the shroud. Once I had that part in, the holes on top were pretty close, and I thought they might be close enough to make it work. I'm considering trying to dremel a bit of that bottom curvature area, especially that large blob of aluminum that seems to contact the left metal bottom mount. It was called out in an earlier thread as a possible culprit.

I don't think I really checked out the fitting of the locator pin... how does one make sure that it's fitting correctly if everything is so tight? Will it slot into place?

And for completeness' sake, I verified that the old mag housing did fit correctly still... I am thinking about doing a test fit with that, then aligning the TDC mark on the crankshaft with a small plastic label so that I can relabel the TDC mark on the vertex housing. It definitely does seem a few degrees off.

I did see several recommendations to just send the housing back and get a new one, but it's actually just *almost* fitting, so i'm hesitant to do that as I haven't driven my car in over a month... Something tells me that i've just got to get used to a dremel anyway, so I might as well use this as a practice opportunity.

getluky · 03-29-2007, 10:02 AM

Also, made some progress with the dremel this morning. I'm sanding down the inner contact area of the fan housing near its outer edge, because that's where that alternator lip gets caught. It is starting to slide further in, so i hope that with a bit more progress I can get a perfect slide fit.

Paul Ferradas · 03-29-2007, 10:23 AM

Hey Gordon, were neighbors

I don't remember using a mallet when installing my alternator. I have an 88 3.2

Any pics of your car?

getluky · 03-29-2007, 10:37 AM

Hey Paul, nice wheels! Do you still have your original magnesium housing?

Here's an "action" shot of my car when it was running, courtesy of David Leong.

where are you at in Santa Clara?

cmonref · 03-29-2007, 10:41 AM

The TDC mark on the Vertex housing should line up with the joint between the two case halves. Mine was just a hair off (half the width of the machined mark, if I recall correctly.)

The slot for the locator pin was a bit narrow. I had to do a little work with the dremel to make the pin fit against the stop when the housing is in the correct position.

Better to make the capscrew hole in the fiberglas a little bigger to fit the hole in the housing than to crack the fiberglass trying to force the capscrew in later.

Paul Ferradas · 03-29-2007, 10:43 AM

Yes, I still have the housing, I took the alternator off to beadblast the fan.

I live right next door to Great America on Agnew.

Is that all your working on right now?

Sonic dB · Sonic dB's Garage

Very important: I bought one of the Vertex housings for my 86, when Vertex
first came out with them about 4 years ago. It didnt fit into the shroud.
I tooled it down and it still didnt fit. I called Vertex and they sent
me a second one which did. Do a search in this forum and you
will see that this is a very common occurance with the Vertex
housings. Call them and have them send you another one.

getluky · 03-29-2007, 10:47 AM

Sonic, was it a really tight fit at the fiberglass fan shroud, and did the capscrew holes match up perfectly? Also, did your alternator slide in without any sanding?

The tolerances on this one are off, but they're pretty close, enough that I can kinda taste it, and I hate to go through another round of 2 way shipping before driving my car again. =(

Paul: it's the only major thing i'm working on right now - i'd love to powdercoat my fan, but i'm super antsy to just get the car back on the road.

getluky · 03-29-2007, 10:52 AM

Brian, good tip about the screw holes, when/if I get that far i'll definitely do that.

getluky · 03-30-2007, 08:55 AM

I spent some time lastnight trying another test fit of the housing, and started to detect some cracking where I was prying the fiberglass fan shroud up.

I may not be a good mechanic, but I'm at the point where I can tell that i'm about to go too far and break something.

I decided to call in to Vertex, and they're shipping me a new part that should arrive next week. I was even tempted to try using the magnesium housing temporarily, but I rationalized that the whole point of this exercise is to have a working, sturdy part in place. Sigh. Another week!