lutz

How often should the auto tensioner itself be replaced?

Ski

remember that the 944 tensioner is just that, a tensioner, it is not automatic. The 968 has an auto tensioner.

Replacement - if the spring breaks. Most of the time you can sort of "pop" the tensioner and it will be very close to perfect tension but the belt tension should always be checked for accurate setting.

Evan70

From the 944 FAQ (http://www.connact.com/~kgross/FAQ/944faq05.html):
"1987 and later 944's have an automatic tensioning device built in that in theory allows you to perform this operation without the special gauge. However, the automatic tensioner has been known to produce incorrect settings. Moreover, Porsche found that the 944S2 suffered from cam timing belt slap when tensioned with only the automatic tensioner. The bottom line is that the P9201 tool should still be used on the 87 and later cars with the automatic tensioner."

My understanding of this means that the tension should be set/verified using the tool when the belts are changed, but that you then don't have to keep checking the tension after that. I'd probably change the tensioner at least every other belt chane just to be safe.

lutz

Yes i do plan to check the tension.....tensioner was replaced at the last belt change, i just wanted to know if it should be done every belt change or can go maybe two belt changes.

APKhaos

So, if a new cam belt is installed and tensioned with P9201 to the [higher] new belt spec, what is the drill for retensioning this puppy??

Ski

You lock the tensioner down with two nuts, once you lock it, it's just another roller. If it had to be replaced every other belt change, then I'd get rid of both of mine and go back to the 86 roller style. The word "automatic" is false in this context and there is no need to replace it every other belt change.

jerome951

Tony, since you have a good feel of what a properly-tensioned belt feels like, I'd just suggest resetting the tensioner after the first few events and feel it. I reset mine each winter (maybe during the driving season if I'm in there) using the tensioner, and after the first few retensions it doesn't change much.

I've also reset the balance shaft belt tension by hand. Use the 0.5mm between idler and belt test. Seems to work OK.

DAR951

1) Wait the requisite time/distance (2000 miles +/-... enought for the belt to fully stretch);
2) Borrow (again) the 9201 tool from Jerry;
3) Repeat the tensioning proceedure with the "used" belt specs...

DAR951

Sorry, but you must have the best calibrated hands on the planet... First time I ever used the 9201 thought I'd do what you suggest... guess what??? The adjustment is so fine from what is OK to what is way off (according to the 9201 gauge) there is no way you can repeat the results by feel.

Now you may argue, and I know a number who do, that it's "just a belt" and the tension isn't that critical... however, that's a different arguement. IF you believe getting the belt tensioned to withing factory spec is important, you pretty much have to use the gauge every time...

APKhaos

Agree completely with Don on this one. The 'feels right' technique leads to wildly variable readings in teh gauge - I tried it. The Kriket drove me crazy, and did not deliver repeatable results. First time I've used it, and there is some technique and practice required. The 9201 delivered repeatable readings every time - first time I used it.

jerome951

I agree that if you want it within factory specs everytime that the gauge may be required (not sure if the tensioner is consistent enough to deliver this).

However, I've talked to many technicians and other owners who have never used a 9201 and use the belt-twist method without belt breakage or slippage.

Guess it all depends on your risk tolerance and access to a 9201.

FWIW, I've never tried setting the tension by hand on a new belt or even the first re-tension (my hands aren't calibrated). After the belt has stretched and been retentioned using the 9201, I reset the tension every year or so w/ the auto/manual tensioner. Guess my risk tolerance isn't too high....

rcarpen22

Speaking of the 9201, where is the best place to purchase one of these from a price standpoint?

F18Rep

I hope to have a 9201 clone on the market in about 2 months - working through testing/calibration of a prototype now... Bruce

rcarpen22

That's good news. What do you plan to charge for the clone?

IceShark

My situation may be a bit unusual, but for my upcoming replacement of cam, BS belts and rollers I have been offered the loan of the 9201 tool by five different people. If you are a contributing member of the Porsche community there are a lot of other members that will come to your aid. I'm glad I don't have to use that damn Kricket tool.