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Old 12-26-2012, 12:58 AM   #1
lowesguy
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? on catalytic converter

my catalytic converter is making really bad noise,lots of rattling,makes the truck sound like s_ _t!,it was replaced about 30k ago,the original one was huge compared to what they installed,whats on there now is a free flow cat,but driving on nasty roads up in the wine country has loosened its guts,right now I don't have the cash to have it replaced,so.... I was thinking of cutting it out with my sawzall,and gutting the insides then have it welded back up there,the truck is a 78 3/4 with a 3" exhaust flow-master muff, any one ever gut their Cat?
I have to have one for smog tests here,and I just passed it last month with cleaner readings than my 300E I rebuilt!
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Old 12-26-2012, 01:04 AM   #2
motornut
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Re: ? on catalytic converter

Check the heat shield isn't loose over top it
I'd get a pipe made to replace it?
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Old 12-26-2012, 01:39 AM   #3
lowesguy
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Re: ? on catalytic converter

Ill crawl under tomorrow,but last time I checked it out pretty sure its the insides are loose making the racket, few months back I got some heavy duty wire and lashed it to the frame,helped but noise still there,wish I could put a straight pipe on it.
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Old 12-26-2012, 03:01 AM   #4
bohmankid
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Re: ? on catalytic converter

I gutted the cat on my Camaro. It really has no noticeable effects for performance, but it's easy to do. I cut it off, stabbed the insides with a long screwdriver, and welded it back on.
If your cat is bad, get under there and hit it with a hammer. If its bad, it'll rattle.
If your truck runs clean enough, it should pass the sniffer. (All of my trucks pass without cats). It'll also pass the visual test if you put the gutted cat back on.. Good luck with your project.
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Old 12-26-2012, 07:39 PM   #5
lowesguy
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Re: ? on catalytic converter

I'm stoked! I did it! I cut the back pipe 2" behind cat,moved rear pipe to the side,then with a crow bar broke the insides apart,all that loose honeycomb came out,now will take it to a muff shop for one weld! sounds so much better now,doesn't sound like I have a bag of bolts rattling around!
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