I just installed the engine after a rebuild and this noise started soon after it got up to temperature. This noise is coming directly from the bell housing/slave cylinder area. At the 11 and 16 second mark the pitch of the noise changes as the clutch pedal is pressed and released. The rear wheels are on ramps so I haven't seen if engaging the clutch in gear has any effect. Findanza flywheel, 930 disc, stock PP and clutch didn't have this noise prior to rebuild.

link to vid...

http://www.youtube.com/watch?v=fsAzE...ature=youtu.be


Any ideas? Thanks!

 

Minor update..
I put the rear of the car on jack stands and engaged the clutch while in gear. No change, the noise happened.
I removed the alternator belt, balance shaft belt as well as loosened the t-belt a bit. The sound was still there.
Initial start of a cold engine there is no noise but as the engine warms up the noise slowly starts to get louder.

 

Hmm, the change in noise when the clutch pedal is depressed leads me to think it's the throw out bearing. Did you replace that during your rebuild? If so, maybe you got a faulty one??

 

Throwout bearing is new. I didn't replace the pilot bearing because it felt fine and this noise didn't exist prior to rebuild.

Im at a loss on this one. I really DON'T feel like tearing into the clutch assembly again.

Thanks for the reply

 

Either drive it as is or accept that you may have to tear into it again. =( See if it gets worse. Last thing you want to do is tear into it, not ID the problem, put it back together, and it still makes noise.

Really exacerbate it so you know what the problem is when you go back in (visible wear, part failure, etc!)

 

Driving it is one thing I haven't tried yet. I could drive it around a little and see if anything changes. I have a bad feeling that Ill be removing the clutch again. I would like to have an idea of what it could be before removing things. As you noted, digging in, finding nothing and have the sound come back after assembly would be a GIANT waste of time and energy.

Thanks Ben.

 

Come to think of it, though, it might not be the throw-out bearing. Mine makes a slight chirping when cold (it's not very old) but the chirping goes away when the clutch pedal is depressed and the bearing stops spinning.

I think your issue lies elsewhere. Try to think of things that are always turning. Have you tried looking at the speed sensor to see if it's rubbing on the ring gear?

 

No speed sensors on this build. I'm using a TEC3 for management. The MAG sensor gets a reading from the toothed wheel at the crank pulley and I can see that it is not touching.

What makes this even more elusive is that this noise does NOT change as RPM changes. As the engine is warming up, the sound slowly comes on and remains, just as in the video, until it cools. Other than pressing the clutch pedal, I can't affect the sound at all and pressing the clutch has a barely audible effect. Pulling vacuum lines, adjusting air/fuel ratios, idle speed, in/out gear....nuthin!

 

Other than Pilot or Throw-out Bearings which would change, only thing I come up with is the Air Blower Motor Bearings.

 

From what I have witnessed the noise came on as the engine got up to temp. Thinking that its temperature related I turned on the heater and cycled through the fan speeds. I think the air blower motor that you mentioned is the same blower that gets turned via the 'fan speed dial' on the dash? If so then changing the fan speed didn't change things. Good thinking though!

A friend, who helped me finish the motor install, thinks its vacuum related. There is vacuum at the intake upon initial cold start. As temp increases does the vacuum 'pull' get changed or routed differently? A vacuum controlled subsystem that activates at higher temps??

 

i'm pretty sure that theres something rubbing in there, sounds like plastic/hard rubber rubbing on metal to me! I haven't been into the clutch housing so I cant really comment on what it could be, is it coming from the back for sure?

 

Fairly positive that it is coming from the bell housing area. I was under the car while it was running and from that view you can almost pin point the area. I tried the screwdriver to ear (stethoscope) trick on most points on the bell housing but I was not able to verify what part was generating it. Right now the only thing I can think of is the pilot bearing. Would a bad or dry pilot bearing make a noise like this???

 

Could it be the guide sleeve? Any chance it was installed crooked or bent while the clutch was apart?

 

Wow that is a bizarre noise!

So it doesn't change with RPM, only engine temp. And your friend thinks it might be vac related. And it's coming from the bell housing area. And it's kinda plastic-y sounding.

One thing I can think of that's near the bell housing, has vac and coolant going to it, and is made of plastic... is the heater control valve. Perhaps you cracked it when installing the motor and the noise you hear is air seeping past the seams (or a crack) in the valve?

Try pulling the vac line to it and see if the noise goes away? Just an idea.

 

Turbo17 -- The guide sleeve is new and I don't see how it could accidentally be installed crooked. I believe it can only be installed one way.

Omni -- It is a very bizarre sound indeed! Its similar to a belt that is rubbing on a seized pulley. I have asked multiple friends to watch the video just to get a different perspective on things. I asked a foreign auto mechanic to come over the house and listen. He has been a mechanic for 30 plus years and he is stumped as well. Everybody says the same thing... 'engine sounds great but that noise is ****ed up!'

The heater valve is new and I did unplugged that vacuum line to test.. no change. I have been kneeling on top of the engine and laying underneath while it was running and the sound is definitely coming from bell housing area. I can see the flywheel spinning and has no wobble to it at all. At the end of the video, when the engine is stopped, the noise increases slightly. This slight increase in the noise pinpoints the location to the bell housing. Something about the change in pitch allows you to 'audibly' hone in on the area.

At the moment the running theory is that the pilot bearing needs to be replaced. Why this noise started now is anyone's guess. I would of though if the pilot bearing was going I would of heard something when the engine was running before the rebuild. The car is on 4 jack stands now. Could there be some pre-load on the drive shaft because its not 'properly' resting on all 4 tires? The TT slid very easily into the bell housing nothing needed to be pried or forced into place.

How about air in the coolant?
How about air in the slave cylinder?
Anyone know of a way to test the pilot bearing? I could drop the tranny, unbolt the TT from clutch bell housing, slide the TT back a bit. That would pull the shaft out of the pilot bearing. Start warm engine and listen...maybe??

I know I'm grasping at straws but laying on a cold slab of concrete, removing the drive train to replace a part that might fix it, is not very appealing.