Jay W

I replaced the timing belt and pullies on my 968, the first 968 I have worked with. I have done several timing belts successfully on 944s and was familiar with how the spring loaded tensioner works. The 968 has a different setup with a hydraulic tensioner and I followed the bits and pieces of instructions that I could find about removing and reinstalling it.

Now my timing belt seems to be running to the rear of the cam pulley and almost is touching the engine rather than staying centered.

So to anyone that has done timing belts on a 968, is there a washer on both sides of the lower pivot stud of the tensioner swing arm? I only saw one and didn't pay enough attention to the back side to see if there was a second one, or really if the washer was on the circlip side or the back side. I put the washer on the circlip side. Could I have bent that pivot stud arm? Is it possible to install the tensioner pulley backwards? I had a 928 that had plastic bushings on its pivot and the plastic broke as I changed the belt. The belt then ran to the front of the cam gear until I replaced the bushings because the arm was able to wobble to one side or the other.

I used the proper method to compress the hydraulic tensioner so I dont think that is the problem.

Anybody with a picture of the tensioner swing arm setup or a diagram of the parts?

Jay W

Ok for anyone with a similar problem and searching for answers, I took it apart and can say what is not the problem.

There is no way a washer could have come off the backside of the tensioner stud when I took off the tensioner. There are rubber o-rings on the tensioner stud that would keep a washer from coming off the stud. The only washer on my car was on the front side behind the clip. It is possible that a previous mechanic lost a rear washer but they would have had to take off the o-rings to do it so I doubt it.

Also when I checked the pivot stud to see if it was loose, it was not. Also it would take some real pulling with a breaker bar to bend that pivot so that was not the problem either.

So that leaves the copper sleeve on the aluminum pivot arm. Apparently it is worn slightly and that is giving just a bit of play at the pivot bolt. This translates to about 1/8 inch of movement at the top of the arm. This allows the tensioner pulley to be leaning slightly to one side and that angle pushes the belt to the back of the cam pulley. I even made a washer for the back side to see if it helps take out some slack which it did not.

So after all the testing and the one possibility that the o-rings help to keep it lined up and they could be worn, all I had to do was put it together and make sure the tensioner arm is sitting in the right position. The pressure of the hydraulic tensioner is holding it in place after I pulled it to the correct alignment.

To really fix it I suppose replacing the copper sleeve is what I would have to do. But since the tensioner had that play in it before I got to it and the belt was riding properly, I will just keep an eye on it. Hope this helps someone else with the same problem in the future.

krystar

u prob swapped the timing belt tensioner with the balance shaft belt tensioner.

one is inside out, the other is outside in.


... oh wait u got a 968...i have no idea what those pulley setup looks like...n/m

FRporscheman

Jay, sorry I didn't see your post the first time around.

What I would try is to go to hobby shops and/or hardware stores, and find a brass tube the right diameter. Maybe you can try mcmaster-carr. If there is nothing the right diameter, just go to a machinist and have them make you a new brass sleeve, it shouldn't be more than $20. Good luck!

DANNiE

Pictures would help...

FRporscheman

I know exactly what part you're talking about, and I have noticed that brass sleeve before. Strangely, that pivot is not greased from the factory - on all my cars, I use grease to prevent the problem you unfortunately have.

Jay W

Thanks for the responses. Unfortunately I always seem to forget the camera before I get knee deep in dirty grease and I cant go back into the house to document what I see.

This is definitely a different tensioner setup than the 944 and 944S have. I have borrowed the picture of the belt setup from a for-sale post by Matt Sheppard. The tensioner is the vertical bar in the center. The hydraulic cylinder putting pressure on the tensioner is at the upper end on the right. The pivot and copper sleeve is at the bottom of the vertical bar which is obscured in this picture.

FRporscheman has the right idea, and I had oiled the pivot the first time around but it seemed to have more play when there was oil. I will try to replace the sleeve next time I am in there.