Fan Belt Proper Tension

[Tobydog61]

I am replacing my fan belt as a part of a valve adjust on my '88 Carrera 3.2. I have 5 shims under the pulley and one on the outside and the new belt is quite tight. Does a new belt typically loosen early on or should I move all 6 shims under the pulley?

Just a note, the old belt had four shims under the pulley and 3 outside?? not sure why someone went with 7 total shims but I assume 1 additional on the outside wouldn't affect anything.

Thanks

[boyt911sc]

Originally Posted by Tobydog61

I am replacing my fan belt as a part of a valve adjust on my '88 Carrera 3.2. I have 5 shims under the pulley and one on the outside and the new belt is quite tight. Does a new belt typically loosen early on or should I move all 6 shims under the pulley?

Just a note, the old belt had four shims under the pulley and 3 outside?? not sure why someone went with 7 total shims but I assume 1 additional on the outside wouldn't affect anything.

Thanks

Toby,

I changed the old fan belt of my son’s ‘87 Carrera 3.2 last weekend and found 7 shims too. But my SC’s have only 6 shims. Curious to check the number of shims in my ‘89 cabriolet.

Tony

[proporsche]

always only 6 shims...unless the guy like to have spare shimm handy..just kidding..really 6 it is
Ivan

[smadsen]

Use the correct belt, CONTITECH AVX 10X710. Start with 3 & 3 shims. Total six only. If it squeaks at all, go to 4 & 2 or until it stops squeaking.

As a personal note, and not all will agree, I run it as loose as possible and tighten it only enough so it doesn't squeak. I think if it doesn't squeak, it's not slipping.

[47silver]

Check out gates krikit 91107 it is easy to use

[Tobydog61]

I have the correct Porsche 710 belt. I’ll move all 6 shims under the pulley and see how it feels.

[winders]

The "trick" I used was to get the belt tight enough so I could not twist it with my thumb and index finger no more that 90 degrees.

The 10x710 belts don't fit into the pulleys as nice as the OEM 9.5x710 belts....

[proporsche]

Originally Posted by winders

The "trick" I used was to get the belt tight enough so I could not twist it with my thumb and index finger no more that 90 degrees.

The 10x710 belts don't fit into the pulleys as nice as the OEM 9.5x710 belts....

^^^^^^^^^^^^^^^^^this^^^^^^^^^^^^^^

[Bill Douglas]

After you have fitted the new belt and done a few drives, check the belt tension again. They bed in slightly and become a fraction more lose than when you first fitted it.

[Tobydog61]

Thanks, I’m going to put all 7 shims inside the pulley and see what that looks like. I’m wondering if mine had 7 shims because they needed all of them inside the pulley to get enough slack? Will watch closely first couple hundred miles.

I am amazed how much detail is left out of the articles regarding this maintenance item. Nobody mentions how the spindle on the fan is keyed and how any outer shims have to be aligned correctly or you distort the spacers.

[Bill Douglas]

It's a bit of an IQ test Toby, and I must admit I failed the first few times. I had trouble balancing the shims on the shaft but found a glob of sticky oil stuck them together making the job a lot easier. Mine can either be too tight or a little too lose. I opted for the little too lose and sprayed some "belt dressing" on it which makes it not slip.

[stevej37]

Originally Posted by 47silver

Check out gates krikit 91107 it is easy to use

I use the krikit also for my Vilano belt driven bike. Works the same as for my 911's
Easy to use and accurate.

[psychoideas]

Originally Posted by 47silver

Check out gates krikit 91107 it is easy to use

Good info.

What tension do you set your belt to. on the gauge?

Cheers,
Frank

[47silver]

I set mine to 15-23 Kg cold which is ~ 30-50 pounds.
when you press the Krikit properly it actuall clicks and the lever will move to the line for the tension.
I set it about 30 pound or 15kg.

[psychoideas]

Originally Posted by 47silver

I set mine to 15-23 Kg cold which is ~ 30-50 pounds.
when you press the Krikit properly it actuall clicks and the lever will move to the line for the tension.
I set it about 30 pound or 15kg.

Great information, thanks very much. I have ordered the tool.😀

Cheers,
Frank

[stevej37]

You can also use your smartphone with an app from Gates.
It senses the harmonics when you lay it on the belt and snap it.

[psychoideas]

Originally Posted by stevej37

You can also use your smartphone with an app from Gates.
It senses the harmonics when you lay it on the belt and snap it.

I looked at that app and it asks if I'm tensioning a bicycle or a motorcycle.

[stevej37]

^^^ Understand....I was looking at it for my Vilano belt bike. I bought the Krikit instead.

[stevej37]

[dan88911]

I replaced the fan belt on my car when I first purchased it some yrs. ago.
I did not realize one of the shims had fallen down into the shroud when I was removing everything.
I like flash lights.