Fan pulley not sitting right

[Christien]

I might be overlooking something completely obvious, but I can't get my fan pulley to sit right. I had it off to check the shims for belt tension (having alternator issues and checking everything) and now it won't go back on properly. It was on fine before. I noticed immediately as when I fired up the car, there was a rubbing or even clanking noise from the pulley. I measured distance from the outer rim to the edge of the inner fan area, and there's as much as 1/8" difference from one side to the other.

Another question while I'm at it, regarding shims, I've looked at the parts diagrams and wracked my brain - did the pulley nut, as installed at the factory, have a cap on it? Is this the danger of bottoming it out? Mine is a 22mm regular open nut. For the life of me, I can't figure out the purpose to the outer shims, except in the case of a nut with the cap, where there's only so much thread available. In my case, there's unlimited thread, as it's open-ended.

[kach22i]

I hate these shims.

The shims can slip and make everything go wonky.

I've twisted shims so badly that I had to take a hammer to them and flatten them back out.

Use all the shims, there should be a tech article on this, look it up and look at the pictures.

In the past I have used some gummy wads of roofing tape mastic to tack/stick the shims in place to prevent them from sliding off center as I tighten the nut.

Maybe others have better tricks they will share.

[Jerome74911S]

I just put on a new outer pulley-half and new fanbelt and I can't get the thing straight either. From what I've read, you fasten the belt in place (don't know about your open nut arrangement) and give the starter a whirl without starting the engine. Readjust and repeat till the tension is correct. I can't do this readjusting business because the engine is out of the car with no starter, but this seems to be a reasonable - if tedious - procedure to follow.

[James Brown]

Try a dry run without the belt on just to see what's going on with the shims and the pully. Sometimes this helps and yes, the shims do get cocked.

[Walt Fricke]

Christien

Here't the deal: Only so much of the alternator/fan shaft is threaded. If you omit the cup washer, or you omit putting the "extra" shims on the outside, where the cup edge of the washer squashes on them, you will bottom out the nut.

Which means that the pulley half will not really be on there tight. What it will do is start working its rectangular slot on the rectangular part of the shaft. After a while, both will be less rectangular, and the pulley half will rotate on its own. The pulley half is easy to replace. The alternator shaft less so.

So be good boys, and follow Dr. Porsche's orders on this one. The total thickness of the shim pack needs to stay the same, no matter which side of the pulley half individual shims are on.

Jerome -just rotate your engine with a wrench on the crank pulley bolt. If you have to take off the engine carrier to get at this bolt, do it, since your engine is out of the car. Tighten nut. Belt gets pinched. Rotate some, which unpinches it. Tighten again. Repeat until done.

I suppose, with engine in car, you could hit the starter to do this, though I have always just reached down with a wrench and turned the crank.

Yes, a PITA. Yes, frustrating as one shim always seems to slip off the outside. But thousands of guys like you have mastered this, so you can do it. Once you get all the shims lined up under the edge of the cup washer, and the nut started just enough that the top washer is just onto the unthreaded part (the part which has an OD about same as washer's ID), they you are basically home free. You just have the belt pinching to deal with, and that's easy.

[Christien]

All of the shaft is threaded, at least on my car it is:

[Walt Fricke]

Thanks for the picture. It shows what we are talking about here.

If the problem is not running out of threads, it is that the nut bottoms on the inner pulley half/fan piece before the outer half is compressed. The cup washer is a cup so it can reach over that center protrusion and bear on the outer shims, which in turn bear on the outer pulley half. But without a full shim pack it still won't do the job.

Without enough shims, the cup washer will be tightly compressed against the end of the protrusion, but won't be pressing hard enough on the outer pulley half.

For that matter, I think the cup washer is a candidate for occasional replacement: if you really crank on the nut, you can bend the cup washer and it won't reach in quite as far as it used to. I've got one in my collection with the center kind of dished in.

[Christien]

Ok, pulled it off, reinstalled, the pulley's on straight, but now I see that the noise is actually the fan blade rubbing, right around 5:00. WTF? It's never done this before.

[E Sully]

Is the fan housing strap correctly torqued. You didn't over tighten the fan belt? Bad alternator bearing? Alternator retaining bolts secure?
Maybe take off the belt and check for any play in the shaft. Hopefully not a cracked housing.

[Christien]

Strap is very tight - didn't torque it, but it's definitely on securely. I've been experimenting with fan belt tension, trying to diagnose an alternator issue. Alternator retaining bolts - ?? Do you mean the 6 nuts that go on the bolt posts when the alternator is inserted into the fan housing? If so, they're fine - just had it out last week. Shaft is solid.

My thought is that the belt is overtensioned, thus pulling the entire assembly downwards, hence the rubbing at 5:00.

[steely]

It looks like you can see the scoring at the 5 o'clock housing position in your previous photo.

+1 on what Ed Said above. Does is hit the housing when you spin it w/o the belt?

(And yes, to your earlier question, there was a plastic nut cap from the factory).

(I was writing when you posted)

[Christien]

It occasionally hits the housing when spinning by hand without the belt, but less so. Never used to before today.

[E Sully]

I'd pull the alternator and check the housing out.

[James Brown]

The nose bearing on the alternator might be going out, check lateral play (up/down, right/left) in the fan.

[Grady Clay]

Here is a useful thread.

Pulley Shims, Wrong Config?

Best,
Grady

[john walker's workshop]

the housing may have cracked supporting webs. look through the fan blades at each of the 3 webs for cracks. they can crack on the inside too and not be visible until the housing is pulled out. the webs hold the center alternator mount. and use a bit of white lube on those alternator threads or they will be toast.

[rusnak]

You might have to also check the tightness of the alternator mounting nut/stud at 10 through 11 o'clock position. If it's loose, then tighten and the fan will be pulled away from 5 o'clock. Re-check with a feeler gauge.

I had a severely cracked fan shroud that eventually failed, and just before it did, the scraping was at 6 o'clock, due to the belt. The cracks eventually connect and you have to replace the shroud when that happens.

As for the shims, next time try installing the nut finger tight on clean threads. Then push the shims in line with a small screwdriver, then tighten the nut with a socket jut a little bit. Turn the fan with the spanner tool, then tighten some more. Turn, tighten, turn tighten until you have it on.

If you can't align the shims under the cup washer, then back the nut off a little, then try again to re-align them. The trick is to use finger tip control on the shims with one hand while pushing the pulley against the belt with brute force with the other hand. It's one of the tricks you have to learn when working on Porsches. That, and you should clean threads with a wire brush if they're dirty or rusty. Might as well wire brush that area after wiping it down with some penetrating oil.

[Christien]

Alright, tons of great stuff here - thanks guys! unfortunately I won't be able to try them out until tomorrow night at the earliest, but I'll go through all the suggestions here and report back then or Wednesday.

[al lkosmal]

Originally Posted by Christien

Ok, pulled it off, reinstalled, the pulley's on straight, but now I see that the noise is actually the fan blade rubbing, right around 5:00. WTF? It's never done this before.

There is a beveled washer/spacer, approx 3/16 thick, that is installed at the base of the alternator shaft. This spaces the fan away from the alternator and keeps it in the proper position to keep from rubbing on the fan housing. Is yours missing perhaps?
I just replaced my alternator, this weekend and had this same problem, which was resolved by swapping in the washer from my old, defunct alternator.

It was also rubbing in the 5 o'clock position.

Regards,

al

[47silver]

I believe the torque on the strap (at least on my 2.7 is 72 inch pounds.

if it is too tight it will bind and break the housing. That is why i have 3 housings.