cat rattle
Thread Starter
Pro
Joined: Feb 2005
Posts: 632
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From: Harrisburg, PA 86 Vert w/ 89 wheels
cat rattle
have a metallic rattling which I believe to be coming from the cat, and I will find a way to check that out on my own very soon, but the question....
If my cat is breaking up anyways and I can't afford to get it replaced right away, should I let it go and live with the rattle or would it be better to break all the plates out of it.
My concern is only for protecting the mufflers and my fuel mileage.
thnx.
If my cat is breaking up anyways and I can't afford to get it replaced right away, should I let it go and live with the rattle or would it be better to break all the plates out of it.
My concern is only for protecting the mufflers and my fuel mileage.
thnx.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
It would be best to replace the cat with a section of straight pipe till you get a hi-flow cat in there.
You may need to have a flange welded to the rear of the "test pipe" and drill it out to fit the rear Y pipe but that should not be a big $$ item.
You may need to have a flange welded to the rear of the "test pipe" and drill it out to fit the rear Y pipe but that should not be a big $$ item.
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
When I bought my 86' last year, the driver's side pre-cat was rattleing. My mechanic said it was definitely falling apart. I drove it like that for almost a year until I got a set of LT headers. I never felt any backpressure, and as far as I can tell it didn't hurt anything. ( but it did make me hum the "Sanford & Son" theme a few times when the rattleing got pretty bad).
Thread Starter
Pro
Joined: Feb 2005
Posts: 632
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From: Harrisburg, PA 86 Vert w/ 89 wheels
Originally Posted by Square
When I bought my 86' last year, the driver's side pre-cat was rattleing. My mechanic said it was definitely falling apart. I drove it like that for almost a year until I got a set of LT headers. I never felt any backpressure, and as far as I can tell it didn't hurt anything. ( but it did make me hum the "Sanford & Son" theme a few times when the rattleing got pretty bad).
Honestly thats probably more along the lines of what Im gonna have to do. Long tube headers and hi flow cat are in my plans, but the valve seals come first. I just wanted to hear that it's safe to run for awhile like that.
Pro
Joined: Oct 2003
Posts: 506
Likes: 12
From: Savannah GA
When that pre-cat breaks up it will clock up your main cat.
You'll know it! So if you do it before it breaks up your main cat won't be ruined.
When the car will barely make 50mph pull over in the shade, open the hood, run the engine for 30 sec or so at about 2000rpm (beacuse that's about all it will do). See the exhaust manifolds glowing cherry red? You have a plugged up cat... (It won't be the fuel pump because when that goes it will make a couple of miles and that will be the end, it won't run any more)
I pulled the entire system off my 87 and cleaned it out. All it took was was a BFH and a old piece of 1/2 pipe about 4ft long. Do the main first, then bend the pipe enough to get down to the pre cats.
Took a couple of hours. Cost: "0"$
Spray down the bolts good and let them soak, all mine came out without a problem.
I can't tell much difference in anything except the sound, it made it quite a bit louder.
IF it a cat plugs up you can drive it home. It might try and heat up, just don't give it any more gas than it will take. If it gets really plugged up you can beat on the converter and loosen it up.
JS
You'll know it! So if you do it before it breaks up your main cat won't be ruined.
When the car will barely make 50mph pull over in the shade, open the hood, run the engine for 30 sec or so at about 2000rpm (beacuse that's about all it will do). See the exhaust manifolds glowing cherry red? You have a plugged up cat... (It won't be the fuel pump because when that goes it will make a couple of miles and that will be the end, it won't run any more)
I pulled the entire system off my 87 and cleaned it out. All it took was was a BFH and a old piece of 1/2 pipe about 4ft long. Do the main first, then bend the pipe enough to get down to the pre cats.
Took a couple of hours. Cost: "0"$
Spray down the bolts good and let them soak, all mine came out without a problem.
I can't tell much difference in anything except the sound, it made it quite a bit louder.
IF it a cat plugs up you can drive it home. It might try and heat up, just don't give it any more gas than it will take. If it gets really plugged up you can beat on the converter and loosen it up.
JS
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Originally Posted by Square
When I bought my 86' last year, the driver's side pre-cat was rattleing. My mechanic said it was definitely falling apart. I drove it like that for almost a year until I got a set of LT headers. I never felt any backpressure, and as far as I can tell it didn't hurt anything. ( but it did make me hum the "Sanford & Son" theme a few times when the rattleing got pretty bad).
You got lucky. Doesnt mean it will always be this way!!!
