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Irritating noise MHhhhh
#1

Mhhhhhhhh that is how it sounds .



around 60kmph its there at 62kmph it's gone , and between 100kmph and 110 kmph it's there and gone again .



It is not a wheelbearring because they are all new since yesterday .



first i thougt it came from the front , but after taking a ride in the passenger seat , i think it's from the rear .



it 's not very loud but always there at the same speed and like turning a switch on/off , there is a little difference in loudnes once the car heat's up tire's an engine .



it is there regardless of clutch operation , in or out of gear , the only time i can make it go away is when ik keep the throttle on en not accelerating and no breaking on the engine just in-between(the best i can discribe it , but it is very difficult to keep i there , and it is only a fraction of a second , but it seem to be gone .(in gear 3456 n0 difference )



Tires , pinionbearring , exhaust ???



I first notised the noise after i had my rims powdercoated last winter and drove the car again in the spring , put on fresh rear tires , but i am not sure if it was right after that .



Also it did not change at all(the sound ) during the 3000 miles i drove the car this year .



Also changed the transmission oil , no difference .



changing the wheel bearrings was a good thing since they had some wear on them , mostly the left rear , drivers side .



Any suggestions ????
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#2

If it is the pinion bearing it will manifest itself as a high pitched wail, not unlike jet engine.
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#3

I would look for a harmonic rattle. If it's there at 60 and 110 (almost 2X) I would suspect you have just reassebled some flashing or cowling that is quite close to a suspension element.
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#4

[quote name='DaveN' timestamp='1324757736' post='119564']

I would look for a harmonic rattle. If it's there at 60 and 110 (almost 2X) I would suspect you have just reassebled some flashing or cowling that is quite close to a suspension element.

[/quote]

I thougt off that but there is nothing i can find looked everywhere , and the only thing i can think off is , maybe something vibrating inside the rear part of the exhaust , but changing it just to find out $$$$$ .

All the heatshields etc are good , also the whole exhaust has new rubber and i replaced one off the metal hangers because one off the bolts was rusted and broke .



It is just irritaiting , also because most people don't even hear it til i point it out .

And then the comment don't drive between 100 and 110 , the 60 noise is only during accelerating and slowing down , ik can live with that , but the other one is at a speed i drive a lot of the time



but we will keep on digging until it's gone .



Grtz
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#5

does it do it regardless of gear? (trying to nail down if it's speed or rpm or a bad gear)



i agree with the harmonic theory though as the most likely. there are a couple of shields that will do this, and not show it by merely seeing if they are loose. you have to bend them and release them and listen to the noise they make to see if it is the same noise.



that being said, tires are a possible culprit. try turning at that speed to apply a side load to the tires, and see if it remains. then, drop 10lbs of air out of them and see if it remains (remember to re-inflate)



while not likely, it's possible that it's a wheel bearing. did you only change the front?



it's also possible that it's a torque tube bearing, but you should be able to eliminate that one by changing gears and seeing if it remains.
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#6

I had tires on my other car that caused such a noise at certain speeds that someone riding along with me thought I had a bad bearing! That person was a mechanic by trade and was not convinced when I told him it was road noise from the tires. As soon as I got new tires, noise was gone!
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#7

[quote name='flash' timestamp='1324855391' post='119594']

does it do it regardless of gear? (trying to nail down if it's speed or rpm or a bad gear)



i agree with the harmonic theory though as the most likely. there are a couple of shields that will do this, and not show it by merely seeing if they are loose. you have to bend them and release them and listen to the noise they make to see if it is the same noise.



that being said, tires are a possible culprit. try turning at that speed to apply a side load to the tires, and see if it remains. then, drop 10lbs of air out of them and see if it remains (remember to re-inflate)



while not likely, it's possible that it's a wheel bearing. did you only change the front?



it's also possible that it's a torque tube bearing, but you should be able to eliminate that one by changing gears and seeing if it remains.

[/quote]

It is speed related , engine rpm or gear do not affect it at all .

You notice it the most when in 6th gear because there is less engine noise(rpm)

Wheel bearings are all new front+rear .



Tires is my best bet since it sort off developed after powdercoated the rims , but then again i did not drive the car a lot in winter time .

But i'll try the over/underinflation bit see if it makes a difference .



And i.ll start fiddeling with everything under the car , heatschields etc .
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#8

[quote name='Langley968' timestamp='1324860047' post='119596']

I had tires on my other car that caused such a noise at certain speeds that someone riding along with me thought I had a bad bearing! That person was a mechanic by trade and was not convinced when I told him it was road noise from the tires. As soon as I got new tires, noise was gone!

[/quote]



I had skilled people in my car , and i am affraid i am one off them , worked as a mechanic myself for a while , now it is only hobby , and done some restoring on cars , metalwork engine's etc , last project i did a 55 chevy Nomad , took it to France for my last vacation .

So i know one or two things , but just can't find it .

But keep the suggestions coming , i will find it .



Grt's Olaf
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#9

Wheels out of round?

You say that it happened after you powder coated the rims...maybe they got dinged during the remount of the tires?

Brian
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#10

[quote name='SILVY968' timestamp='1324954843' post='119638']

Wheels out of round?

You say that it happened after you powder coated the rims...maybe they got dinged during the remount of the tires?

Brian

[/quote]

Put the tyres on myself , and also did the balancing part , have the machines in my hobby barn for that , they are perfectly round and have no issues.

Also i would have know , and the sound does not mach a out off round problem , the car would woblle up and down or be shaking .



Sorry but English is not my native langauge , so i am doing my best .





Spend a few hours looking at the bottom part off the car today , i have a car lift so no problem , and have been fiddeling around with heatshields and the plates behind the brakes , found one canidate for the possible noise , but no luck , the noise is still there .



Positve part is car is getting more an more quiet , an i am for 99% convinced that it is a tyre issue .



Next thing is trying the underinflation bit from Falsh



Also since i always wanted the 17inch cup 1or 2 wheels i'll start looking for them , i prefer original ones .

They seem kind off hard to find for a decent price , but puting those on will rule out another probale cause .





Greets
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#11

Update ,



did a belt job , and put a new waterpump in , old one had the bearing going bad , had a little hope it had something to do with the noise but since it speed dependant .

No such luck .

Instead of trying the underinflation bit , instaled a set of 99393 Cup (93 Cup (93 Cup (93 Cup (93 Cup (93 Cup (93 Cup (Cup 2))))))) wheels i picked up today , but again no luck .

Put the car up on stands at the rear and i am pritty sure the sound is from within the gearbox , it does not sound like the pinionbearing noise (compared with the audio sample in another topic ) and it is not very loud , like i said most people don't even hear it .





Guess i keep on driving for now , i did find a different gearbox and since it is from a CS it might have the <acronym title='Limited Slip Differential'>LSD</acronym> in there , if it does i might go for that , an upgrade and a almost sure fix for the noise .



Also i am thinking of puting in new differential bearrings , i understand it can be done with the gearbox in the car ??

Anyone done this before ?



Olaf





And
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#12

Fixed with a rebuilt exchange gearbox , not sure what it was , but my bet was still the pinion bearring .

Also synchros on first where going bad .



Grtz
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#13

Try unplugging the variocam. It would actually make the noise in all gears if this was the problem, but perhaps easier to notice at speed.
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#14

[quote name='jfrahm' timestamp='1329102584' post='121770']Try unplugging the variocam. It would actually make the noise in all gears if this was the problem, but perhaps easier to notice at speed.[/quote]



Thanks but it was the transmission , i have a rebuilt one in there now and the noise is gone .
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