Fan pulley issues

[Daver22]

Curious what others think. I have a decent rattle coming from my alternator fan area. I have isolated to here - I can see a out of round issue with the tensioner cap area. I ordered replacement parts from our host. I took a couple pics today with a bright flashlight and can see metallic dust/fragments. I don’t have the pulley wrench (one of the parts I ordered) so it will be a couple weeks before I get to pull it apart, but thought why not get some opinions from you all.

Your might have to zoom in but you can see it bright metallic “dust” in the pulley.

This car new to me and my first 911 (1987 targa) as well. I have fairly decent mechanical capabilities but always like experts thoughts first!

Thanks in advance.





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[mikesarge]

Have you tried backing the fan "strap" bolt off about 1/8 of a turn?

[TeeJayHoward]

It’s possible that the previous owner didn’t put the proper number of shims in there and now the fan is being shredded. Made that mistake myself, cost a grand to fix. To check, pull off the half-pulley and look at the fan where it slides over the alternator shaft. Also count the number of shims - should be six total, if memory serves. Tension is increased or decreased based on what side of the half-pulley they’re installed on.

Got some pics from my experience with that here

[GH85Carrera]

A rattle from that area can certainly be the alternator itself. If the bearings are worn out it can rattle some.

[RSTarga]

The belt looks really deep into the pulley and a bit frayed.
Take the fan belt off, check how many shims. Start the car without the belt for a few moments to see if the noise goes away. Put a new belt on and tension properly using the shims that are there for this purpose.
If the noise is still there with the new belt, it is probably your alternator bearings as mentioned above.

[Daver22]

Thanks for all the input. I have to wait for parts to arrive, late next week. Hoping it’s the pulley/shim issue and not the fan that’s been damaged.

Will update in a couple weeks. Thanks again


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[HarryD]

Originally Posted by Daver22

Thanks for all the input. I have to wait for parts to arrive, late next week. Hoping it’s the pulley/shim issue and not the fan that’s been damaged.

Will update in a couple weeks. Thanks again


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As a reminder, you MUST have 6 Shims for the pulley. They are either between the pulley halves or on the outside under to cup washers. This makes sure you alternator nut is not bottomed out.

[Daver22]

UPDATE: got it all apart, not easy! The outer half of the pulley was wobbly after I cut the belt. Figured no shims must be there. After some creative tries I got it apart. And NO shims present! The spindle on the alternator had some wear similar but not nearly a bad as TeeJayH shows in his thread. See pics below. I remembered there were a couple small parts that came with the car (I have had it about 6 weeks). Sure enough, zip tied together are six shims! Not new but in fine working shape. Somebody didn’t know what they were for when they put a belt on??

New shims, belt, outer pulley half, tension cap, nut and pulley wrench on their way to me from PP. But for now when I put 5 shims between pulley halves (per recommended place to start) the outer half seats properly (center is a bit worn out of shape but not bad) it snugs up well with the sixth shim on the outside u see the tension cap.

Will replace all when new pieces arrive with the new belt and see how it goes. Nothing to lose trying new parts.

Also, started the car with belt off, smooth and quiet. It had a top end rebuild 2500 miles ago and literally has no leaks. So relived to have isolated it to the alternator fan area. Even if it means a new alternator and fan, that’s less than an internal crankcase issue!

Will keep updating post new parts and time to get them in. Thanks again for the earlier input.










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[TeeJayHoward]

Originally Posted by Daver22

New shims, belt, outer pulley half, tension cap, nut and pulley wrench on their way to me from PP. But for now when I put 5 shims between pulley halves (per recommended place to start) the outer half seats properly (center is a bit worn out of shape but not bad) it snugs up well with the sixth shim on the outside u see the tension cap.

Ouch. That fan needs to be replaced. (I didn't see a new fan in your list.) If you don't replace it, the shims will slide into the grooves on the fan and the whole thing will be out of balance. It'll tear up the shims and the half-pulley while rattling your alternator around.

The fan should look like this:


No grooves at all in there.

[Daver22]

Yeah I figured that would be the likely outcome. I will get one ordered up so I don’t have to mess around. Can I get the fan pulled while alternator stays in the car? Any tips or experiences?


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[Daver22]

Just ordered the new one. Would rather know all is correct and not have to worry about it. Still open to experiences pulling the fan (while still in the car).


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[TeeJayHoward]

Originally Posted by Daver22

Yeah I figured that would be the likely outcome. I will get one ordered up so I don’t have to mess around. Can I get the fan pulled while alternator stays in the car? Any tips or experiences?

You can. It just slides over the threaded shaft on the alternator. It's held in place with a locating/woodruff key and the nut/shims/pulley you're already acquainted with.

Basic steps to remove it:
1) Remove nut
2) Remove the tension cap
3) Remove shims (if any), noting the number
4) Remove half-pulley
5) Remove fan belt
6) Remove shims, noting the number
7) Pull fan towards you, possibly wiggling as you do so
8) If fan blades contact rear of engine bay, tilt fan as needed and continue removal

Installation is the reverse of disassembly.

You were basically one step away from having it removed with what you've done already. The woodruff key should be solidly inserted into the alternator shaft, but there's a slim possibility that it's loose. If you hear anything fall off while you are removing the fan, make sure that's not it. Aside from that, I can't think of any real "gotchas". The alternator is secured to the fan housing, which is secured via the strap to the engine case. You shouldn't need to worry about them during the procedure. The fan blades are likely to be dirty, so wear gloves. You should be able to remove the fan with muscle and effort. If you try to resort to a pry-bar, you're going to have a bad time.

[917_Langheck]

After you install the new fan have your old one refurbished. There are folks here who can restore to better than new. You can then sell it to recoup some of your cost of the replacement fan, or keep it and sell your new one.

[Daver22]

Sounds good. Thanks folks. Will see if I can get the old one off tomorrow.


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[Daver22]

Final Update:

New fan from host installed. Good news, old fan came off pretty easy. First tug on it and no movement. Tapped around the hub, sprayed some penetrating oil on the alternator threaded shaft, did a few applications, waiting 10-15 mins. Next pull and it came off with about 3 tugs with my hands.

New fan went in, all 6 shims used! Nice tension (4 shims inside, 2 outside).

Going to get original fan refurbished (new hub) with Joe Leggs. Will get that sent out over the weekend (he said about three weeks to turn it around). Will keep the aluminum aftermarket fan on for now - keep original to replace when I wish to do so.

Thanks to everyone who commented, great help. Feels good to have that done. Runs quiet, all is good!!

FYI - I have a pic of the new fan installed, but getting error when trying to upload.


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[TeeJayHoward]

Originally Posted by Daver22

New fan from host installed.

Grats, man. I recommend a celebratory drive around some local twisty roads!

[Daver22]

now it works!


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