Belt Tensions - HELP!
 

Hi there,

Ever since I got my 944 (1984 2.5 Lux) about a year ago now, I noticed a whine from the belts.

The previous owner claimed that they had just been tensioned by his local Porsche 'specialist' - but I had my doubts.

I did notice that the alternator belt seemed pretty tight, so wondered if the whine was coming from this.

Anyway, I finally got around to checking the tension myself this week - using a Krikit tension tool. I did not want to strip too much of the enigne down, so just removed the centre cover to inspect the general condition of the belts, etc.

Given the limited space, it has only been possible for me to check the balance belt tension so far. What concerns me is that I'm getting a consistent reading from this of 65lbs. If my memor is correct, then the balance belt is usually the slackest of the two belts and ususally around 40lbs.

Could someone tell me what the recommended figures are for belt tensions using the Krikit - also, I guess having the belt this tight is probably why I'm getting the whine.

I suppose that having run with the belt too tight for some time, this will have prematurely aged the belt - so I'm probably in for a belt change.

Any help and advice will be gratefully received.

Thanks,

Ian.

The belt whine on my car was from the balance belt tensioner being set incorrectly. I did not know that there's a clearance both above and below this tensioner - it's why it has the slot for the mounting bolt. Anyway, I went back in and redid it correctly and no more whine.

The procedure is on clarks and bruce arnn's web site. Bruce also has krickit info on his site.

Thanks for the info AKCJ - I'll check out Clarks and Arnworx.

Ian,
With engine cold:
The balance belt is 28 pounds on the Krikit-(just mentally mark a spot below the 30 pound slash)
The cam/timing belt is 40 pounds.

The ACCURATE use of this guage is practice and repetition. You must place the guage (black foot) in the same place on either belt. SAME PLACE. Repeat test 5 to 10 times or until your arm swells and gets tired:).

You must retard your timing belt back 1 and 1/2 tooth (read tech below) The PO should have a mark on the crank pully (or his mechanic)

Here is a very good write up:
http://www.arnnworx.com/tensioningbelts.htm

If you have any doubt about your cam belt, CHANGE IT $12.00 Pelican Parts

Good Luck
John_AZ
1988 924S + 1987 924S

To get an accurate reading on the cam belt you've gotta remove the balance belt, the cam belt idler and water pump guide, too. Many owners back off the tension on the balance belt till it stops whining and don't bother measuring. Even at 28 pounds the balance belt's still a little tight (the krikit seems to have a problem measuring in small increments). Get a leather glove for your right hand so that while you're cranking the engine over by hand you don't shred your knuckles.

Thanks for this very useful feedback John-AZ and Slam.

I know what I'll be doing at the weekend!

Thanks again,

Ian.