A scratching noise at ~2800 rpm
#16
Rennlist Member
Thread Starter
Karl I can't really pick up the noise that well... if it goes away when you push in the clutch it might be your throwout bearing. Can you roughly tell where the noise is? It's a little hard sometimes because the entire drivetrain is rigidly joined and transmits vibrations.
That's actually an interesting thing to check...after work I'll definitely inspect the headers. They are from a late NA 944 which I believe are not as rugged as the early headers.
Not sure if this applies but my '86 turbo had what was a commom problem where the exhaust manifold had cracked at a bracing plate underneath the manifold. Had exactly the same symptoms. It was a known problem and I managed to get the dealer to change it for a re-designed version as warranty work.
#17
Rennlist Member
All I can tell is that it's coming from what I think is the front of the car? But it's still the same noise that your description matches for my car.
#18
Rennlist Member
Sounds like a heat shield to me..or..maybe it's loose substrate rattlling around inside the cat. I had this on my DD a couple of months ago. Rattled like hell, cut open the pipe and took the cat out. Two small pieces of substrate fell out. Otherwise clean as a whistle. Nice open can. Put in a delete pipe. Problem solved. no mice, cooked or otherwise.
#19
Rennlist Member
Thread Starter
A scratching noise at ~2800 rpm
Think I found the culprit. There are 2 hangers on the main body of the exhaust system, the rear one is holding the pipe too high (?) in such a way that it's acting as a fulcrum and the muffler hangers are slack. The hell?
#21
Rennlist Member
Thread Starter
I got that bolt out, I had to remove the bellhousing and pressure plate to do so. The bolt is still awaiting judgement
Here's a diagram to better show what the problem is, pardon the crude drawings:
This also makes sense because a few weeks ago I was getting on it and heard a large bang from the tranxaxle area but nothing seemed wrong. I got under it and saw that the mount bushing for the rear hanger had come out of the bracket, the bang was probably the hanger smacking into the torque tube after the tension was suddenly released...
I took everything off and reassembled it where there wasn't killer tension on that bushing, it was just tight. Are there any likely causes for the stress on that joint? I can loosen the hanger but I don't think that's solving the problem, it was fine for years before.
Here's a diagram to better show what the problem is, pardon the crude drawings:
This also makes sense because a few weeks ago I was getting on it and heard a large bang from the tranxaxle area but nothing seemed wrong. I got under it and saw that the mount bushing for the rear hanger had come out of the bracket, the bang was probably the hanger smacking into the torque tube after the tension was suddenly released...
I took everything off and reassembled it where there wasn't killer tension on that bushing, it was just tight. Are there any likely causes for the stress on that joint? I can loosen the hanger but I don't think that's solving the problem, it was fine for years before.