Balance shaft eccentric tensioners

[bigbrotherjohn]

We are preparing for an autocross tommorow and just wanted to check the belts for any fraying or any obvious stuff. We saw that the balance shaft belt was not touching the upper eccentric tensioner and that the belt seems pretty loose. Is this normal or are the tensioners installed incorrectly. Can we just rotate the tensioners to put some tension in the belt and stop it from flapping around?

both tensioners are all the way to the right, is that OK?





the belt seems pretty loose to me



sorry but i am pretty ignorant as far as 944s go, hope some one can help, and no i dont have any of the special tensioning tools.

[hpaulb]

Yes. The tensioner has backed off. Rotate and tighten the belt. You can use the expensive tool or do as I'v done all my cars. 90 degree rule. On the longest run, twist belt. If you can only hand turn it 90 degrees, it's correct.

[bigbrotherjohn]

So you're saying i should turn the top eccentric tensioner 90deg. and then check that the belt is tensioned like you said. Should i also do something with the bottom eccentric tensioner?

[ae1969]

Originally posted by bigbrotherjohn
So you're saying i should turn the top eccentric tensioner 90deg. and then check that the belt is tensioned like you said. Should i also do something with the bottom eccentric tensioner?

UHMMM NO.

If what I am saying does not make sense. Dont touch it.

1. The bottom one on your picture is the tensioner.

2. The upper one is an IDLER. Once the belt is tensioned it is set at 0.5 mm with a feeler guage.

3. Pull the idler out of the way to check tension on balance belt. If you had the proper tool I would set it around 3.5+- .5. The units dont mean anything so thats why some will use the 90 degree method.......and the proper tool is starting to cost north of $400........
The 90 degree method means you grab the belt in the middle of the run and twist it with thumb and index finger. You should be able to turn it 90 degrees. Not too tight or too loose. Once you are comfortable with that you go to step 4.

4. Install idler. adjust with a 0.5 mm feeler guage and you are done.

BUT really if I were you I would leave it alone.

There are a few details I jumped over....... but thats the general idea.

Too tight belt can snap and take out the timing belt. Too loose .........same thing.

[bigbrotherjohn]

ok, that makes it much more clear, thank you. Judging by the 90deg test the belt seems pretty good actually. Im glad i didnt do anything with the belt, i didnt want to until i was sure i knew what i was doing.