exhaust pic request.
Thread Starter
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
exhaust pic request.
I have an '86 corvette, which I just gutted the cat. After putting the exhaust back on car I have a bad rattle sound that is coming from the pipes. But I cant figure out what is rattling. I had the car on a lift at a friends shop and figured out it was the exhaust, because when you hold the rpm's at a steady 1200 it rattles bad, so I had a friend do that while I was under looking for something vibrating. Got out the trusty screwdriver and touched part of the exhaust on the right side of car just behind precat and the rattle stops, take screwdriver away and rattle is back immediately, and as long as RPM was at 1200 you could do this over and over again. So i'm asking for a pic of how the air tube is running from cat up to engine, as I think this might be the culprit.
Thanks in advance
Thanks in advance
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
When you gutted the cat, did you get any pieces into the exhaust pipes? Could this be the rattle?
The air pipe from the cat is held to the cat with a crush ring. Check to see if this is loose. Then check to see if the tube is rubbing against any body parts on its way to the engine. On my 85 it comes up very close to the exhaust manifold and is clamped to the side of the manifold in one spot.
The air pipe from the cat is held to the cat with a crush ring. Check to see if this is loose. Then check to see if the tube is rubbing against any body parts on its way to the engine. On my 85 it comes up very close to the exhaust manifold and is clamped to the side of the manifold in one spot.
Thread Starter
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
When you gutted the cat, did you get any pieces into the exhaust pipes? Could this be the rattle?
The air pipe from the cat is held to the cat with a crush ring. Check to see if this is loose. Then check to see if the tube is rubbing against any body parts on its way to the engine. On my 85 it comes up very close to the exhaust manifold and is clamped to the side of the manifold in one spot.
The air pipe from the cat is held to the cat with a crush ring. Check to see if this is loose. Then check to see if the tube is rubbing against any body parts on its way to the engine. On my 85 it comes up very close to the exhaust manifold and is clamped to the side of the manifold in one spot.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The other option would be sound waves are hitting the area you described since you gutted the cat. If you think about it....you put the screw driver against the pipe and it stops. Remove the screw driver and it starts again. And it is at 1200 RPM. If you can't see where the pipe is touching the body, take a coat hanger and open it up and thread it around the pipe and then slide it down the pipe to "feel" if the pipe may be touching anything above the pipe that you can't see. If everything is clear, then sound is your problem. A possible solution would be to move the screw driver up and down the pipe to see if there is a special point where the sound stops. If there is then take a ball peen hammer and make a dent in the pipe at this spot. This will change the inside configuration of the pipe and perhaps cancel out "this spot".....doesn't mean that the sound waves may find a different area or RPM.
