Porsche Enthusiasts Club Forum

Hi Folks -
Is it possible to replace the S2 cam belt semi adjustable tensioner with the auto adjustable as fitted to the 968? I have just had my cam belt replaced, but now have a very knock loud noise until warm but I know this (cam belt) can be adjusted to alleviate the noise. Is the 968 tensioner a quick fit?

Thanks -

Dave - SA

Are you sure it is not the balance belt making the noise? That was the culprit on my S2. If the idler is in contact with the belt all the time and spinning like mad all the time then it would make a noise. I adjusted mine by sight so that the idler would only contact the belt when the belt flapped a little (e.g. opening/closing the throttle) and that stopped the noise.

My 968 block has an s2 spring tensioner so no reason it shouldn't work the other way round. You'll need to fit longer studs and cut the belt cover a bit from what I remember.

AFAIK the 968 tensioner is hydraulic, is an S2 tensioner a straight swap ?

If it is a knock then it needs investigating, sure it isn't belt slap?

Yep Paul, the fitting studs are a different length and I think the hydraulic Unit pokes out of the timing belt covers, it's a few years ago now but I may have been concerned that the hydraulic tensioner wouldn't work with the different belt length and pulley size of 16v versus 8v.

Either way the noise needs to be investigated.

Do you have any more 968 blocks laying around James .

Hi All -

Thanks for your replies and feedback!

TR7V8 - your are correct - I should have described the noise as belt slap, as you pointed out! This ugly noise is only there when the motor is cold, then goes away once warm. The Porsche manual recommends a re-adjustment to a new cam belt tension after 500miles or so (back to the garage!). As the S2 tensioner is only semi-auto, thus needing this manual adjustment, the idea of a 968 auto tensioner would alleviate this operation and also allow the correct tension during the belt's life span.

Thanks once again -

Dave

Hi Folks -

I started up the S2 this afternoon and the belt slap noise was yet again there! I left it idling awhile and all of a sudden it died! Never had that before! I started the motor again and it sort of was ok until it conked out again - with but bad running. Being always careful about our engines but knowing about this possible loose cam belt, I think it's slipped a belt cog. The local PC garage is just around the corner - a tow I think, as I don't want the belt to slip again. I had the cam belt changed very recently whilst they were (not the PC) doing a replacement cam chain (not broken, just fore site) with the buffers. I don't think the cam belt was tensioned correctly...Any other ideas from the Forum would be appreciated.

Thanks - Dave SA

It sounds like either the rotor arm has slipped or the belt has skipped. If the belt is slapping then it is bloody lose not slightly. If you have some tools then you'd need to strip the covers off & check the timing marks. Personally for the cost of a cambelt I'd probably change it NOW as if it has ben that slack then it will have undergone all sorts of torsional & tension changes. They should never be reused once the tension has been taken off them & especially if removed. Most of my cambelt disasters have been because of failing to heed the above.