Carrera chain tensioners - sound different?

[mike635]

Did some searching for this but couldn't find anything.

My '81 SC had the updated chain tensioners installed by the previous owner (my brother). The car has always had this turbine-like whine from the engine as it's wound up. It's a cool sound and I always assumed it was from the fan but I had a recent conversation with my brother about it and he claimed that the whine wasn't there before the tensioner upgrade.

An additional note - another family member (different brother, we now have 3 911's in the family ) recently purchased an '89 targa. That engine (stock engine and exhaust) sounds very different than mine (no whine, very deep exhaust tone)

Is it normal for a stock 3.0 with the tensioner upgrade to sound different? I'm not concerned, just curious.

Mike

[Flieger]

Did you check the tension on the fan belt? Tight belt can cause a whine. Also bad alternator bearings, which can themselves be caused by tight fan belts.

[mike635]

Thanks, I have checked the tension and set it to spec with the proper number of shims. The sound isn't bad, it's actually great, just wondered how/why the carrera chain tensioner upgrade changed the sound of the motor and why it sounds so different than a carrera 3.2 motor.

Mabye the tech forum isn't the place for this..

Mike

[yelcab1]

My 80sc before sounded really good, like a turbine taking off. After the hydraulic update, it lost the turbine sound. It is one of the reasons why I think the hydraulic update is overated. I woiuld keep the old tensioner and keep the sound back.

I do understand that they may not be related...

[Zeke]

Originally Posted by mike635

Mabye the tech forum isn't the place for this..

Mike

Maybe not, if you won't listen to advice.

Originally Posted by mike635

Thanks, I have checked the tension and set it to spec with the proper number of shims.
Mike

There is no "proper number" of shims. It varies car to car. You check the tension by checking belt deflection with a gauge.

[Flieger]

There needs to be 6 shims. Or is it 5? Anyway, the total number is the same, you just move them from between the pulley halves to outside the halves.

[4sd911]

It wouldn't by chance sound like this?
YouTube - porsche 74 911 sound.MP4

[mike635]

>Maybe not, if you won't listen to advice

Milt - a little harsh eh? Perhaps my comment was misunderstood, I'm well aware of the procedure for setting the belt tension (thanks to advice from this forum) What I meant by "correct number of shims" was that I had 6 total.

4sd911 - thanks for the video, this does sound similar to my car although mine isn't quite as loud a whine as yours.

Mike

[4sd911]

That's a fresh rebuild, I thought it's quite loud. I haven't found any reason at this point for the noise and I'm continuing with break in it's at 500 miles now. I've searched youtube for the sound of 911 engines and have found a few that sound similar.

[ratpiper71T]

Just a thought. Perhaps it's the belt. I've noticed this sound on other vehicles and it virtually disappeared when I switched to a toothed belt- which is the reason for a tooth belt- less noise and cracks less also.

[Zeke]

Originally Posted by mike635

>Maybe not, if you won't listen to advice

Milt - a little harsh eh? Perhaps my comment was misunderstood, I'm well aware of the procedure for setting the belt tension (thanks to advice from this forum) What I meant by "correct number of shims" was that I had 6 total.

4sd911 - thanks for the video, this does sound similar to my car although mine isn't quite as loud a whine as yours.

Mike

Well, look at your own comment, " Mabye the tech forum isn't the place for this." Kind of a put down to me.

Anyway, it's nice to have 6 shims in all, but it's only the ones inside that count. So, I'll stand on my comment that there is no correct number of shims (for adjustment).

Also, it's nearly impossible to buy a correct fan belt at the FLAPS. All mine come from Pelican or the dealer if necessary.

[Joe Bob]

Tuff luv....