Find the Supercharger

[Brozoar]

New belts and rollers! Took my '83 944 NA out on the freeway yesterday and she's driving like a champ. Only thing is I have the (apparently common) problem of one of my belts sounding like a supercharger - this really high-pitched whistle/whine that doesn't seem to go away.

So I've read that this might have something to do with the balance shaft belt or associated idle roller. Is that the case? I got the Contitech belt and roller kit, for early NA's with the updated water pump. The puzzling thing is, I tensioned the balance shaft belt clockwise, like I was supposed to, tensioned the belt properly to about 28-30 ibs. (I have a Krikit so it's hard to be precise), and yet the idle roller still touches the belt on the top, no matter how I adjust it. After a while, I just got frustrated and settled for the position which made the lightest contact with the belt, but there's supposed to be a gap between the belt on both sides (1mm on top and .5mm on bottom according to one source).

It's simply not possible! Should I just take out the roller altogether, or would that be a bonehead thing to do? Is that even the culprit?

[AA_Ezra]

I had belt whine when i did my belts the first time without any special tools. and it was loud but eventualy went a way..


Did it right this time with the armworx tools and no wine at all.

Just FYI. John_Az knows of another method that requires no tools and has somethign to do with being able to just move the pulley on the pump with a good amount of force . if you can't its too tight.

[Guest765]

Originally Posted by Brozoar

New belts and rollers! Took my '83 944 NA out on the freeway yesterday and she's driving like a champ. Only thing is I have the (apparently common) problem of one of my belts sounding like a supercharger - this really high-pitched whistle/whine that doesn't seem to go away.

So I've read that this might have something to do with the balance shaft belt or associated idle roller. Is that the case? I got the Contitech belt and roller kit, for early NA's with the updated water pump. The puzzling thing is, I tensioned the balance shaft belt clockwise, like I was supposed to, tensioned the belt properly to about 28-30 ibs. (I have a Krikit so it's hard to be precise), and yet the idle roller still touches the belt on the top, no matter how I adjust it. After a while, I just got frustrated and settled for the position which made the lightest contact with the belt, but there's supposed to be a gap between the belt on both sides (1mm on top and .5mm on bottom according to one source).

It's simply not possible! Should I just take out the roller altogether, or would that be a bonehead thing to do? Is that even the culprit?

the roller is not the culprit. your belts are TOOOOOOOO TIGGGGGHT
they are currently BURNING off rubber backing compound onto the faces of all your pulleys and gears. depending on how long you ran them like this they are possibly now structurally unsound and may require you to change them - again!

also, there is a correct direction to turn the tensioner pulley , as well as an INCORRECT direction to tension it. i cannot remember which is which, so i'll let john chime in with that part. this could also be your issue and WILL cause premature failure also!

[Brozoar]

I tensioned them to specs in the Contitech pamphlet - 40lbs. on the cam, ~30lbs. on the balance shaft. Clockwise is the correct direction to tension the balance shaft tensioner, I know because for a day (and about 10 miles) I had it counter-clockwise. =P

Did the water pump check, and the 90-degree twist check, my cam belt seems fine. I don't know of any similar tool-less methods for the balance shaft belt, though. So it's not my roller, my BS belt is probs just too tight? I've read a number of different opinions as to how tight it should be, I've heard 24-30, I've heard 35, whereabouts should I be?

[Guest765]

Originally Posted by Brozoar

I tensioned them to specs in the Contitech pamphlet - 40lbs. on the cam, ~30lbs. on the balance shaft. Clockwise is the correct direction to tension the balance shaft tensioner, I know because for a day (and about 10 miles) I had it counter-clockwise. =P

Did the water pump check, and the 90-degree twist check, my cam belt seems fine. I don't know of any similar tool-less methods for the balance shaft belt, though. So it's not my roller, my BS belt is probs just too tight? I've read a number of different opinions as to how tight it should be, I've heard 24-30, I've heard 35, whereabouts should I be?

with that info the balance belts are probably the culprit - i think.

lose the idea you need to measure balance shaft belt tension. they should be only tight enough to engage the cogs, and also tight enough to prevent vibration when running. any tighter is only prematurely wearing the belts. the tension is really only important on the timing belt.

one way it was put to me when i did my belts is;
"balance shaft belt should only be tight enough to keep them from falling off"

[ERAU944]

i can't believe nobody else has commented on this, the balance shaft belt is the likely culprit. on every 944 i've owned, the balance shaft belt was the noisy one.

structurally unsound? really?

pardon my skepticism fwayfarer, but you are a new member with 56 posts. how long have you owned a 944? you show up on the scene out of thin air and suddenly know every little fact about the 944, many of which are purely your opinions...

all i'm saying is that you come on a little strong telling everyone what they should do, and i'm not too certain you are qualified to be ordering people around like this.


anyway, brozoar:

it does sound like you the balance shaft belt a slight bit too tight, just loosen it up a little bit and you'll be good to go. the spec does have it on the snug side, but remember as a rubber belt it will wear in and stretch a little bit, which means it will also quiet down. when it is properly tensioned it will make noise, but it shouldn't be overbearingly loud.

[flash968]

first off - ezra, never say "no wine" - that is blasphemy - "no whine" is ok though

second - do not use contitech belts - they cannot hold up to the heat over time - they break down very quickly - use gates or dayco

third, it definitely sounds like the belts are just too tight - there should not be a particularly noticeable whine - it should be quite faint

[Brozoar]

Cool cool, I'll loosen it up a bit.

"No wine" is a blasphemy.

Contitech rollers are okay though? Also, just as a side question, do I ever have to worry about my cam belt rubbing against the back belt cover? Or will the belt automatically settle into an okay position? Just a concern - I tried inching out my cam belt from the rear cover as much as I could (very little) just because I was a bit scared.

[Guest765]

Originally Posted by ERAU944

i can't believe nobody else has commented on this, the balance shaft belt is the likely culprit. on every 944 i've owned, the balance shaft belt was the noisy one.

structurally unsound? really?

pardon my skepticism fwayfarer, but you are a new member with 56 posts. how long have you owned a 944? you show up on the scene out of thin air and suddenly know every little fact about the 944, many of which are purely your opinions...

all i'm saying is that you come on a little strong telling everyone what they should do, and i'm not too certain you are qualified to be ordering people around like this.


anyway, brozoar:

it does sound like you the balance shaft belt a slight bit too tight, just loosen it up a little bit and you'll be good to go. the spec does have it on the snug side, but remember as a rubber belt it will wear in and stretch a little bit, which means it will also quiet down. when it is properly tensioned it will make noise, but it shouldn't be overbearingly loud.

sorry, not getting into your e-penis measuring match, champ. sorry i use terms you don't like? a burned belt is now an unsound belt. simple and plain.

[smokin_944]

One thing I've noticed about 944s with excessive belt whine, they often eat waterpumps. I wonder why that is?

[Truckin4life]

Belt is to tight

[Brozoar]

Sure sure, but if we're talking about the balance shaft belt, that has nothing to do with the water pump. I've been keeping an eye on mine actually, and so far no leaking, so *knock on wood*.

[JonA]

The whine has been, for me, always from the balance shaft belt. I have done belts twice with the Arnworks tools and both times with the balance belt set dead to specs there has been a loud whine. You just loosen it a little at a time until it quiets down. I like to hear a little whine so I know I havn't gone too far. It will stretch a little and quiet down on it's own so factor that in. When you are done you will be surprised at how loose it is.
The camshaft belt has to be set accurately with one of the accepted tools.
Don't forget to retension after break-in. I believe the interval is 1500 miles.

Hope this helps,
Jon

[ERAU944]

Originally Posted by JonA

The whine has been, for me, always from the balance shaft belt. I have done belts twice with the Arnworks tools and both times with the balance belt set dead to specs there has been a loud whine. You just loosen it a little at a time until it quiets down. I like to hear a little whine so I know I havn't gone too far. It will stretch a little and quiet down on it's own so factor that in. When you are done you will be surprised at how loose it is.
The camshaft belt has to be set accurately with one of the accepted tools.
Don't forget to retension after break-in. I believe the interval is 1500 miles.

Hope this helps,
Jon

Sounds like my experiences. I'd like to hear about the noises that fresh belts make from someone who uses the 90 degree belt twist method.

[nynor]

balance shaft belt is too tight. some whine is acceptable, IMO, but too much will cause undo wear on bearings and the belt.

i thought this was going to be yet another thread about supercharging the NA....

[Rasta Monsta]

+1 to fwayfarer being off his meds.

Did you try 270° twist on BB belt?

[flash968]

balance belt re-tension interval is 2000 miles for first installation, and then every year or 15000 miles, whichever is first

change interval is 3 years or 45k miles, whichever is first

[968 GUY]

Agree on the whine caused by the belt being too tight. First time I did one, thought it was too loose. Tightened it a bit more and got the whine. Loosened it til there was no wine.
I thought the e-penis measurement was based on number of posts, add extra for repeating wwhat someone else has already stated, and double for stating that the only correct part is the one YOU use.

[flash968]

lol - loosened it until there was no wine - man, i'd have to be doing that for about a month to go through all of my wine, and then i'd have to check in for a liver transplant

anyway, i was correcting the re-tension point, and stating the further required re-tensions, and also the correct change interval, since many people don't know it, and suffer the consequences later - often they think you can go 10 years on belts, just because they have no miles on them, and then find out later that they should have changed them, but unfortunately not before they had their valves crash into each other

as for the correct parts, it's not me dictating this - dayco and gates are the original manufacturer parts - in fact, the design itself was done by them - they are also now back as the porsche certified part (at least as of last week)

that being said, the composition of the conti belt is not conducive to heat and resultantly stretches and loses its elasticity - this is a well known fact and is not hard to find info on - still, because they are the cheaper belt at most aftermarket vendors, many people still buy them - every failure i know of involved a conti, including mine, which is what led me to do the research on the parts, going back to the designers

[Rasta Monsta]

E-penis! Classic!