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Emma's sick

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jaybird

jaybird

Yoda
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Drove her the past 2 days. Noticed what sounded like a bit more 'puttering' in the exhaust yesterday evening on the way home. Newish exhaust, last fall or over the winter.

Drove her today, coming back from my sister-in-law's (25 minute ride) noticed a rattling/grinding noise on acceleration. Became progressively worse by the time I was 5 minutes from home. Temp was fine, oil pressure fine, etc. Not noticeable at idle, but as soon as I put any pressure on the gas pedal.

It's not a valve knock. Not a knock, clunk or rap sound. I checked under the hood and under the car, while running. I can't tell that it's coming more from the engine bay or under the driver side.

I checked the exhaust system, the header for any holes, cracks, or gasket leaks. I couldn't find any.

Any ideas where to look or what it might be?
 
Did you check to make sure the exhaust system isn't touching anything underneath the car or very close to touching anything. I had a very similar sound and the exhaust had warped enough to hit the cross memeber under the seat area when under load. With the engine off there was close to a 1/4 inch of clearance between the exhaust and body but underload it will still hit.
 
Is the sound definately coming from the front? Take a drive with the top up if you are not sure, and listen closely.

Is it associated with engine revving only (sitting still in nuetral), or is it during acceleration only? Does it increase in engine revs, or increase in speed of the car (no matter what gear you are in)?
 
I couldn't see that any part of the exhaust system was touching anywhere it shouldn't.

It's either something under the bonnet or under the driver's side of the car from the seat forward to the engine.

It makes the noise on acceleration, or if I rev in idle. More pronounced the more I rev or accelerate. All gears. And if I drop out of any gear into neutral, it stops.
 
When was the last time you changed the motor mounts? Didn't you just put a different carb/exhaust manifold/header setup on her?
 
Check the bolts (make sure they are tight) holding the exhaust/intake manifolds on - they might have loosened considering the exhaust system is new... also, on mine about 3-4 months after I bought it... It did the same thing... The STOCK exhaust flange on the downpipe had cracked where it bolts to the manifold, and eventually broke completely. If that's the problem, it'll get worse slowly until it breaks completely. I had a local mom-n-pop muffler shop replace the joint for $60.
 
We had a flange issue on her before we replaced the exhaust system. The flange had loosened at the connection and it sort of splayed out the opening bigger or whatever you call it, was noisy like muffler noisy though, not like this. And the floorboard got hotter than blazes until we fixed it.

Hmmm. Floorboard DID seem really hot the last two days.

BRB, going back out and belly under her.
 
Have somebody rev her up while you're under her...if the exhaust moves & bumps the body, you may need engine mounts also.
 
Jealousy? hehehe good advise above /ubbthreads/images/graemlins/iagree.gif
 
I propped something on the pedal to 'rev' her while I was under there looking. None of the exhaust system bumped the body anywhere. I checked the flange, I checked the exhaust manifold, got under her again, looked harder, found this. But I had to take a pic from the engine bay, couldn't finagle under the car with the camera to get it.

[image]
hmmm.jpg
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I wish I could go climb under my cars at random... Working on dirt and fire-ant beds sucks... Takes a whole mental and physical routine just to get me in the mood to go under a car here. A concrete driveway would be a blessing.
 
Wasn't in the concrete drive or garage, she's sitting on the street in front of the house and I'll have rock indents in my knees for 2 days! Dirt would have been welcome!
/ubbthreads/images/graemlins/grin.gif
 
You wouldn't if ya had fire ants there... I'm alergic to there bites, and I have to either move any car I'm working on away from them (nearly impossible around here), or take all my tools and the car to my workplace/job and work on it there... Or, climb under the car knowing I'm gonna have a million bites and be swelled up with achy joints for the next 2 to 3 weeks. (which is what I usually do).
 
That flange isn't bolted, or the studs have broken. Sounded sorta familiar. Take it back to the shop that did the original work (might want to call them to see if they'll even do this) and demand they fix it... It's because the bolts were tightened too much (if they are broken) from some big monkey with an air-wrench.
 
That big monkey would be Chuck.
/ubbthreads/images/graemlins/devilgrin.gif

I'm wondering if the stud(s) broke, because we did have one fabricated when I bought the manifold for $10 on ebay. There was a stud missing...

GRRRRRRRR.
 
Or, if you can feel nuts on the studs (no funny jokes anyone) under there, and a flange on the downpipe... then they replaced the whole flange, but forgot to cut off the old one.
 
Yep, exhaust's broken free....bet if you fire her up, she's louder than normal....you might've been hearing it working itself loose.
 
I did notice yesterday that she was 'puttering' a bit louder than normal. I suspected the flange, only because the floorboards were incredibly hot again (like before when we had the flange problem pre-new exhaust system)

Old flange is definitely off. We replaced the entire system from the manifold back.
 
This time.... Make sure chuck uses hand tools to tighten the nuts on the exhaust... to whatever torque specs the Bentley manual calls for. Sorry I called him a big monkey. /ubbthreads/images/graemlins/blush.gif
 
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