[Cloud9...68]

As far as the re-tensioning question, I understand that if you look at is as a true re-tension (as in, loosen everything, and go through the entire tensioning, and then by definition, the pre-load and clearance-setting, procedure at a fixed interval), as opposed to a procedure where you check the tension, and tighten the belt a specific amount if it is loose, then it makes sense. What I'd be interested in seeing is for any members with the P9021 tool to record the value of the tension when they install a new belt, and then again after a series of fixed intervals to quantitatively monitor the degree of loosening, if any, of the belt tension. Just wondering if it actually loosens over time, or if this is an obsolete phenomenon. But in the absence of this data, better safe than sorry - I agree the belts should be re-tensioned at the recommended intervals.

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[PVC12]

On my 944 I had 22K on the belts when I decided to change them myself. When I opened up the covers, the belts looked new but the timing belt was very loose. I replaced the balance shaft and timing belts, and after about 1500 miles went back in there to check the tension. The timing belt had lost a bit of tension (not much) so I re-tensioned it as recommended. I did not use the Porsche tool, I used an inexpensive clicker type of belt tensioning tool that I purchased from McMaster-Carr Supply ($20).

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[Cloud9...68]

I wonder if this would be a suitable alternative to the P9021 tool:



http://www.amazon.com/OTC-6673-Universal...B000I198J0

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[PVC12]

The problem with that type of gauge is that it is normally used on the outside of the belt, (see photo) :

The outside of the timing belt has limited access due to the plastic guard around it.

Although you may have enough access to use it on the balance shaft belt.

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[Cloud9...68]

The balance shaft belt (along with the A/C and the power steering belt) is the only one that needs to be tensioned - the timing belt is self-tensioning. If you look at the picture in Post #9 of this thread, it looks to me like there might be enough space above the top of the BS belt to use this gauge. It is really big and bulky, though; the P9021 is so svelte and compact, and is a real pleasure to use. Do you have any more pictures of this gauge in action. like maybe more of an edge-on view? I'm having trouble seeing how it works. Thanks.

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[PVC12]

Here is a Tension Gauge ($52) specially made for the 944 and I believe it should work on 968 as well: http://www.arnnworx.com/catalog/index.ph...cts_id=227

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[PVC12]

OK thanks, I learned something new, I did not know that the timing belt of the 968 is self tensioned. I'm still new to the 968 world.

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[Cloud9...68]

Yes, I've seen these. I seem to remember them getting mixed reviews for some reason, though. Maybe I'll break down one of these days and buy a P9021, if for no other reason than to answer my question as to whether these belts actually loosen over time, and how much.

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[Cloud9...68]

[quote name='PVC12' timestamp='1333675195' post='124608']

OK thanks, I learned something new, I did not know that the timing belt of the 968 is self tensioned. I'm still new to the 968 world.

[/quote]

Yes, the 944 timing belts required tensioning, but not the 968. But that's not the worst thing, maintenance-wise, about the 944. Porsche was nice enough to provide a "window" in the bell housing through which to remove the clutch assembly in the 968. In the 944, you have to remove the bell housing, which means removing the torque tube. Ugh. A clutch job on a 968 is still no picnic, but it must be quite an ordeal on a 944.

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[PVC12]

They also sell a higher end tool $175, maybe a good alternative to the P9021:

http://www.arnnworx.com/catalog/index.ph...cts_id=189

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[PVC12]

It seems that the more I learn about the 968 the more I marvel at the progressive engineering that went in the the design of the car. Many of the problems of the previous designs were addressed and corrected or vastly improved. My Hats-off to the Porsche engineers!

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[tamathumper]

Just wait...

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[vliegwielolaf1234]

[quote name='Cloud9...68' timestamp='1333675388' post='124610']

Yes, the 944 timing belts required tensioning, but not the 968. But that's not the worst thing, maintenance-wise, about the 944. Porsche was nice enough to provide a "window" in the bell housing through which to remove the clutch assembly in the 968. In the 944, you have to remove the bell housing, which means removing the torque tube. Ugh. A clutch job on a 968 is still no picnic, but it must be quite an ordeal on a 944.[/quote]



done both . 944 took me about 8 hours .

968 took me about 2.5 hours to change the clutch .



Other hand no <acronym title='dual mass flywheel'><acronym title='dual mass flywheel'>DMF</acronym></acronym> on the 944 $$$$

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[bombfactory]

Regarding what can happen if your balance belt gets too loose - in my case the idler roller was positioned incorrectly (left photo), allowing too much 'flop' in the longest span of the belt. This let the edge of the belt make contact with the edge of a nut (yellow arrow). Not good. See the pile of black belt dust to the right from the belt disintegrating.



   

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[MB968]

Any idea why the idler was not positioned properly?

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[bombfactory]

The shop that did the work got everything else right, except that. I've learned they specialize more on 911s and rarely, if ever, see front-engined Porsches. Real nice guys, but I don't think I'll be going back.

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[tamathumper]

I walked into the Porsche dealership last fall and the service manager said "Wow, we never see those!", so I exchanged pleasantries for a few minutes then left, never to return.

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[Cloud9...68]

Yes, every car has its idiosyncracies, and the 968 is no exception, and even very good mechanics can make big mistakes by not being aware of them.

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