How close is the fan housing from the pulley

caliber60 · 04-28-2007, 04:19 PM

I am trying to put back the fan housing on my '87 911. How close is the fan housing from the pulley?

Thanks,

Danny_Ocean · 04-28-2007, 05:31 PM

Mine appears as if it is touching. You can't even get a fingernail in there. Not sure if this is correct, but it might help with your situation.

cmonref · 04-28-2007, 05:48 PM

On the outer diameter of the housing, behind the red arrowhead, is a slot about 1/4" wide. On top of the case is a positioning pin that sticks up from the case. The slot is positioned over the pin and slid forward (in the direction of travel) until the end of the slot contacts the pin. At that point, it should look like your picture above.

cgh911sc · 04-30-2012, 07:14 AM

Mine appears as if it is touching. You can't even get a fingernail in there.

Is this correct? Anyone?

Is the picture above the way it should be; that close?

88911coupe · 04-30-2012, 08:43 AM

Interesting, this issue has come up a few times lately, me included. I loosened the strap a bit, moved it apart, then snugged up the strap but not as tight as before. So far it's staying where I want it but previously I'd noticed the housing was just touching the pulley and had rubbed a faint groove in the housing.

KTL · 04-30-2012, 11:37 AM

Its really close when installed correctly. If you look on the underside of the fan housing (if you have it removed from the engine so you can look underneath) the slot for the locating pin has a forward stop on it. That prevents the fan from being pushed too far inward. Point being is that this stop leaves the edge of the housing very close to the pulley.

On many of the fan housings i've handled, the shape of the lip on the housing has either been flattened near the pulley or machined thinner to clear the pulley.

cgh911sc · 05:39 PM

So,

Is the fingernail distance between the fan housing and pulley correct
or should I try to loosen the strap to create more room?

KTL · 04-30-2012, 09:38 PM

You should try to make more room. I checked my housing on a '87 3.2L and I was mistaken about the stop. The housing on my '87 is stopped by a step in engine case. The clearance of my single pulley from the housing is about 1/8 inch. I took a few pictures to help describe.

First is the ridge on the engine case that the fan housing butts up against

Second & third are pics taken from directly above, as straight-on as possible w/out having the alternator shaft get in the way of the camera.

cgh911sc · 02:53 AM

Thanks Kevin for the pic's. They truly help!

My pulley is directly under the housing about a finger nails width
from each other. I think my housing is up against the rim and pushed forward as far as it will go.

The car runs fine and I don't hear any noise coming from the pulley.

It's a little strange how the pulley and housing don't seem to move at all
not even a millimeter. As long as they stay put and don't move at all then I
think all is okay but wow how close they are to each other and if that is normal is the question I guess.

The belt seems to be perfect. Some might say a little tight but the belt is new and is as I would expect. I used 2 shims on the inside and 3 on the outside with a total shim count of 5 which is how it was before I replaced the alternator, painted the fan, housing, strap etc.

So, I'm thinking about adjusting the strap to see if it helps but not sure it is wrong as it is.

Thanks again for your reply!

KTL · 05-02-2012, 02:25 PM

If you can't get any movement rearward to clear the pulley, then you should be good. The clearance between the pulley and the housing seems to have varied over the years. Some housings like my 87 are cast without any machining in them near the pulley. Others i've seen have the TDC mark area machined flat.

As long as your belt lines-up OK and you're happy with the position of the housing? I say leave it. The strap does nothing to locate the housing. It simply clamps it down.

And whatever you do, don't over-tighten the strap. So many housings get damaged from people cranking on the strap until the ends touch together. By that time, the fan housing has likely cracked or is going to crack..... It simply needs to be mildly tight so the housing is snug under the strap and can't move at all.

The general rule of thumb is six shims total for the fan pulley. Six should give you enough thickness to ensure the nut on the shaft doesn't run out of threads. However most alternators nowadays are remans that have plenty of thread on the shaft and there's no worries about the nut bottoming out on the unthreaded portion of the shaft.