Help with this stupid rattle - Page 2

garyabc · 09-25-2009, 06:29 PM

Kevin,

When I saw your post I went right out to the driveway, put the car up on jack stands and tightened the "pinch bolts" that clamp the torque tube into the transax'. The nuts look like they could be brass (?!) so I drew them up 1/2 a turn. Test drove the car but it didn't help.

Driving with my head out the window, it sounds like the noise is further forward. Passenger agrees. It seems to be under the car in line with the center of the door.

So I raised the car again to see if there was another clamp further forward, but of course there is not. This time I tightened everything I could find under there, but still no change.

Magk,

My noise has an underlying clicking sound, like turning a ratchet quickly. No hissing though. I may try to make a quick recording of the sound and post it.

garyabc · 09-25-2009, 10:39 PM

Here's a 30 second clip of my noise:

http://www.youtube.com/watch?v=KB3hqrfJm3M

944Ross · 09-25-2009, 11:13 PM

Try it with light pressure on the clutch pedal

thirdgenbird · 09-26-2009, 10:16 AM

ive got a similar noise as well, i'm don to thinking mine is down to the cat or torque tube.

garyabc · 09-26-2009, 10:35 AM

Hi Ross,

Drove around with varying amounts of clutch pressure. There doesn't seem to be any change in the noise. There's no noise when the clutch is disengaged. It's difficult to get the clutch to slip and still get the engine RPM up on deceleration, but with light clutch pressure there's no change in the sound.

The engine speed that this occurs seems to have moved from 3200 RPM to 3500 when I tightened the torque tube clamp. I'm going to see if there's a torque spec for those, or any alignment requirement.

garyabc · 09-26-2009, 10:41 AM

Thirdgen,

If I get inspired, I may put the straight pipe back in and see what the dif is.

RockStar951 · 09-26-2009, 01:12 PM

I have the exact same sound on my 951. I currently have a straight pipe / no cat. So you might want to rule that out. I was under my car today to try to diagnose this problem to no avail.

whalebird · 09-26-2009, 03:29 PM

Dudes, get a mechanics stethiscope. Sears, Harbour Freight all have good ones. You have to have one anyway if you are going to own a Porsche. It may be helpful to jack up the car and lightly tap on everything, especialy exhaust, with a rubber mallet. You will find the culprit with these tools.

garyabc · 09-30-2009, 11:18 PM

OK whalebird,

Got the stethoscope.
Do you know anyone that I can duct tape under the car to listen for the noise while I drive?
If I over inflate the tires I think I can get close to 6 inches under there.

thirdgenbird · 09-30-2009, 11:28 PM

Quote:

Originally Posted by garyabc

OK whalebird,

Got the stethoscope.
Do you know anyone that I can duct tape under the car to listen for the noise while I drive?
If I over inflate the tires I think I can get close to 6 inches under there.

yeah, my thoughts exactly... pretty hard to listen to an "in gear clutch out" noise under a car. maybe 4 treadmills and a creeper? i'll watch...

garyabc · 09-30-2009, 11:42 PM

Plan to do the timing and balance belts tomorrow (my first time). If that goes well I'll have to decide whether to search for the mystery noise again, or just wait to see if it gets worse. Was hoping someone would recognize it.

Photodan · 10-05-2009, 10:36 PM

I don't want to freak you out but I had a similar sound under the exact same circumstances, very RPM specific. Ended up being a pinion bearing starting to go, even though the sound seemed further up and nothing like what I thought a bad bearing would sound like. Pull the rear carpet and padding out (you'll be surprised at how much more mechanical noise you can hear without all that stuff in the back) and go for a spin until everything is really warmed up. You might try a smooth road with a incline and go down in a low gear so the engine is doing the braking in the RPM range that it makes the noise.

KevinD · 10-06-2009, 12:26 AM

Have you tried religion yet?

Sorry it wasn't the simple answer I had. I was so relieved it wasn't the pinion on my car. Sounds like yours could be, though. You've tried everything else! Damn, that has to be frustrating!

09-25-2009, 11:13 PM	#18
944Ross Addict Rennlist Member Join Date: Dec 2008 Location: Rio Rancho NM (ABQ) Posts: 773	Try it with light pressure on the clutch pedal __________________ '86 944/2 ..........'52 Ford F-1.......... '91 H-D FXRS-C '94 Mustang GT.......... '69 Triumph Bonneville

10-05-2009, 10:36 PM	#27
Photodan Addict Rennlist Member Join Date: Jul 2008 Location: Birmingham, Alabama Posts: 81	I don't want to freak you out but I had a similar sound under the exact same circumstances, very RPM specific. Ended up being a pinion bearing starting to go, even though the sound seemed further up and nothing like what I thought a bad bearing would sound like. Pull the rear carpet and padding out (you'll be surprised at how much more mechanical noise you can hear without all that stuff in the back) and go for a spin until everything is really warmed up. You might try a smooth road with a incline and go down in a low gear so the engine is doing the braking in the RPM range that it makes the noise. __________________ Daniel Taylor An Aussie in Alabama 1990 944 S2

09-25-2009, 06:29 PM	#16
garyabc User Join Date: Sep 2009 Location: Connecticut Posts: 28	Kevin, When I saw your post I went right out to the driveway, put the car up on jack stands and tightened the "pinch bolts" that clamp the torque tube into the transax'. The nuts look like they could be brass (?!) so I drew them up 1/2 a turn. Test drove the car but it didn't help. Driving with my head out the window, it sounds like the noise is further forward. Passenger agrees. It seems to be under the car in line with the center of the door. So I raised the car again to see if there was another clamp further forward, but of course there is not. This time I tightened everything I could find under there, but still no change. Magk, My noise has an underlying clicking sound, like turning a ratchet quickly. No hissing though. I may try to make a quick recording of the sound and post it.

09-26-2009, 10:16 AM	#19
thirdgenbird User Join Date: May 2008 Posts: 451	ive got a similar noise as well, i'm don to thinking mine is down to the cat or torque tube.

09-26-2009, 10:35 AM	#20
garyabc User Join Date: Sep 2009 Location: Connecticut Posts: 28	Hi Ross, Drove around with varying amounts of clutch pressure. There doesn't seem to be any change in the noise. There's no noise when the clutch is disengaged. It's difficult to get the clutch to slip and still get the engine RPM up on deceleration, but with light clutch pressure there's no change in the sound. The engine speed that this occurs seems to have moved from 3200 RPM to 3500 when I tightened the torque tube clamp. I'm going to see if there's a torque spec for those, or any alignment requirement.

09-26-2009, 10:41 AM	#21
garyabc User Join Date: Sep 2009 Location: Connecticut Posts: 28	Thirdgen, If I get inspired, I may put the straight pipe back in and see what the dif is.

09-26-2009, 01:12 PM	#22
RockStar951 Addict Rennlist Member Join Date: Oct 2008 Location: Miami, FL Posts: 49	I have the exact same sound on my 951. I currently have a straight pipe / no cat. So you might want to rule that out. I was under my car today to try to diagnose this problem to no avail.

09-26-2009, 03:29 PM	#23
whalebird Addict Rennlist Member Join Date: Nov 2004 Location: Blue Ridge Mountains NC. Posts: 1,422	Dudes, get a mechanics stethiscope. Sears, Harbour Freight all have good ones. You have to have one anyway if you are going to own a Porsche. It may be helpful to jack up the car and lightly tap on everything, especialy exhaust, with a rubber mallet. You will find the culprit with these tools.

09-30-2009, 11:42 PM	#26
garyabc User Join Date: Sep 2009 Location: Connecticut Posts: 28	Plan to do the timing and balance belts tomorrow (my first time). If that goes well I'll have to decide whether to search for the mystery noise again, or just wait to see if it gets worse. Was hoping someone would recognize it.

10-06-2009, 12:26 AM	#28
KevinD Addict Rennlist Member Join Date: Dec 2007 Location: Boise, Idaho Posts: 34	Have you tried religion yet? Sorry it wasn't the simple answer I had. I was so relieved it wasn't the pinion on my car. Sounds like yours could be, though. You've tried everything else! Damn, that has to be frustrating!