Fan / belt issue at the end of my rebuild
 

I'm at the end of my rebuild. Literally all I have left to do is install my clutch. Hopefully.

I've got an issue with my fan and fan belt. As part of the rebuild, I replaced the alternator. Now I've got my new alternator seated in the housing, and the fan mounted on the shaft w/the key. It spins freely and there is no interference. I've hooked it up and tightened down the mounting strap. I made sure that the fan housing was seated on the locating pin in the cradle that is a part of the case halves. The fan housing doesn't interfere with the crank pulley; there is about 2mm or so clearance between them. They do overlap very slightly in the vertical plane.

Problem? I can't get the fan belt to tighten. My hardware configuration for the fan pulley is: Stepped/backing washer, key, fan, 2 shims, outer pulley half, 4 shims, cupped washer, fan nut. But trust me, going to 0 shims inside and 6 outside wouldn't change things. The fan belt is really loose at this point. Lots of deflection and no way it will be turning if I fire up the motor.

What could I have done wrong? I took a look at my old fan belt which I still had around, and it is the same size as this new one. So I don't think there is a problem with the belt itself.

Ideas welcome, and hopefully I'm just doing something foolish.


http://forums.pelicanparts.com/uploa...1198708569.jpg

http://forums.pelicanparts.com/uploa...1198708595.jpg

Gulp. Thought of something.

Is it even possible to install the pulley on a 3.2L carrera motor backwards? I.e. so I am trying to hook up the fan belt to the AC side of the pulley, which appears to be ever-so-slightly smaller in diameter? Or is that an impossible mistake to make?

Hopefully that's it, and I can just pull engine tin, lock the flywheel, pull off the crank pulley nut and flip it, and then put things back together. Verification that this could indeed be the problem would be appreciated.

The pulley face that mounts up to the crankshaft has a pin sticking out that fits into a hole in the crank face. If you put the pulley on backwards, two things would probably happen: (1) the pulley would not be "locked" onto the crankshaft because the pin does not stick out of what is normally the outer face, and (2) you would not be able to put the washer on the now-outer face of the pulley because the pin would be in the way.

On your picture, the smaller diameter pulley seems closest to the motor. On my 3.0L, it is the opposite. So I cannot tell 100% that your pulley is backwards because yours is a 3.2L, but it seems it is. Look for the parts diagrams in PP catalog maybe...

Aurel

I bought two fan belts for my 3.2L and found the same thing. I stuck the old one on there and it's nice and tight. Odd. They are both marked the same too. Did you actually test out your old belt to see how it fits? I thought too I did something wrong.

OK, there's no way I screwed that up. Crud, thought that was the problem.

I'll check out the old belt again, but I don't think that is the issue. Other ideas?

There are only a few areas that could be at fault;
1.) different diameter pulleys now being used versus old
2.) alternator cocked at angle, not mounted correctly
3.) different length belts

1.) using the same pulleys as before, right?
2.) if the alternator were cocked, there would be interference between fan blades and housing when turning.
3.) more than likely the belts. While the belt might have been "in spec" when it left the factory, remember we Porsche uses a rather arcane way of adjusting tension. There isn't really margin of adjustment to speak of.

I have purchased a belt from the local Porsche dealership here in Appleton and found the tension to be too much!! The belt was rock hard even with all the shims on one side. These damn Conti Belts are out of Porsche 911 spec, plain and simple.

Hello there,

The same thing recently happened to me during my final touches of my 3.2L rebuild, I too purchased my fan belt from this site and I suspected the wrong one was sent. It turns out that there was nothing wrong with the belt, the guys at pelican recommended that I try turning the engine over in order to allow the belt to seat properly. Since my engine was still on my stand I turned the engine over manually by turning the alternator pulley bolt. After about one rotation I immediately noticed my belt seated better and wallah! It actually was tighter, I was now able to make small adjustments with the shims to get the desired result, I recommend trying it. Good luck, AlexSmileWavy

Dertermined,
I'm not sure if you were addressing me, but the high belt tension was AFTER the engine had turned over several times. Thanks.