Anyone disassembled a Catalytic Converter? - PeachParts Mercedes-Benz Forum

John Plut · #1 03-03-2007, 11:56 PM

The cat on my '88 260e has a bad internal rattle. Appearance-wise it looks very solid on the outside. I don't want to shell out the big $ for a new converter and thinking about either deforming the outside shell with a big clamp, or putting some screws through the outer shell to hold whatever is loose in there.

I believe there is a core element inside but is there also a case around the element? I was hoping if someone could describe what is inside it would help me with my plan.

Jim B. · #2 03-04-2007, 12:58 AM

I gutted one once on a 1977 Olds 88 Delta royale coupe that I had. It was a 350 4 bbl.V8 with a single exhaust, and one of those Monolith GBM converters.

Drove the front of the car up onto a set of ramps, turned off the motor, crawled underneath and with a HUGE allen wrench loosened the plug on the bottom of the cat, got in the car and started it up, in Park, and revved the engine again and again.

It sprayed platimum pellets out the hole all over the place, then all of a sudden I realized they might be worth something. I gathered them up off the ground and put them in a metal honey tin (Damn near filled it up, too!).

After a while, no more of them sprayed out the hole, so I figured they were pretty much out. Then I simply screwed the allen screw back into the bottom of the converter. No one would ever be the wiser, it would pass the visual inspection just fine! Car ran fine, maybe even better, after that.

But that wasn"t enough for me. I drove it to Nevada and found a VERY accomodasting exhaust shop who fabricated a dual exhaust system without any cats at all.

THAT REALLY woke up the car, it was an instant hit on the schnellstrasse.

Of course it was a big problem when I sold the car, had to eventually get it put back to factory, again, to pass California smog, so I threw out the dual system, a single exhaust with a used cat on it. :fork_off:

If the catalyst has a drain plug on the bottom, maybe this would work on your car too?

Mercedes cats are pretty expensive, and maybe if you removed it, and EVERYTHING inside, and assembled it back it could pass the visual if you got into it from the top side..maybe?

cool · #3 03-04-2007, 01:05 AM

Dana, an actress for all season. love the way she performed in the series "kidnapped".

Parrot of Doom · #4 03-04-2007, 07:01 AM

You can't screw into a cat, its a honeycomb of lightweight precious materials. It would just turn to dust.

The cheapest option would be to cut a panel in the housing, get a big screwdriver, put a breathing mask on, and destroy the innards of the cat. Then weld the panel shut and forget about it.

ILUVMILS · #5 03-04-2007, 10:41 AM

Anyone disassembled a Catalytic Converter?

Late model MB cats' do a great job of disassembling themselves!

Kestas · #6 03-04-2007, 10:43 AM

The catalytic converters I've worked on had a ceramic monolith with honeycomb cross section surrounded by a ceramic felt blanket.

I agree with P of D. Pinning the monolith with screws would only fix it temporarily. Fretting from vibration during use would destroy this setup in short order.

If John goes the 'destruction' route, he may be able to access the monolith from the exit side of the converter with a crow bar and avoid the cutting and welding.

Another option is to do nothing. As long as the monolith is intact, it'll still function. But once the monolith starts breaking up, he'll get exhaust restriction which will reduce high end performance (accelerating and high speed driving). Then he'll have to fix it.

Both (all four?) converters on my buddy's 98 ML320 are rattling. It's no wonder MB is at the bottom of Consumer Reports reliability list. Just another nail in the coffin.

John Plut · #7 03-04-2007, 10:47 AM

...fortuately, I live on the rural fringe where emissions testing isn't required.

I think I'll drill a hole in the cat today and see what might be making the racket in there. I realize the core of the cat is a lightweight honeycomb, but there is something heavyweight rattling around in there. If I could just drill into it or wedge it tight somehow maybe I can stop the racket.

John Plut · #8 03-04-2007, 10:54 AM

...just saw your post. What you describe makes sense. The felt blanket may be gone and the core is probably loose.

Breaking up the core would be an all or nothing option. I wouldn't want to leave anything that would clog my relatively new mufflers.

I think I'll order some new exhaust gaskets, take the whole headpipe assembly off and work on it standing up.

Parrot of Doom · #9 03-04-2007, 11:00 AM

Quote:

Originally Posted by John Plut

...fortuately, I live on the rural fringe where emissions testing isn't required.

I think I'll drill a hole in the cat today and see what might be making the racket in there. I realize the core of the cat is a lightweight honeycomb, but there is something heavyweight rattling around in there. If I could just drill into it or wedge it tight somehow maybe I can stop the racket.

You're risking parts of the cat coming loose and making their way back into your engine. Its a low risk, but particles can get back in there.

Open it up and rip it out.

Kestas · #10 03-04-2007, 12:48 PM

Under what conditions can bits get back to the engine? The engine would have to suck a huge volume of exhaust gases to make it that far. I believe the cat is about three feet from the engine.

For that matter, the risk is extended to any car with a converter that is breaking up. His actions won't increase that risk any further.

Strife · #11 03-04-2007, 05:16 PM

Supposedly, the original mid 70's cat converters used quite a bit of platinum and were definitely worth recycling for the platinum content (platinum now: 1200/troy oz, 12/lb). I think newer ones use a lot less and also use palladium, which is a a lot cheaper.

truckinik · #12 03-04-2007, 05:45 PM

Quote:

Originally Posted by Strife

Supposedly, the original mid 70's cat converters used quite a bit of platinum and were definitely worth recycling for the platinum content (platinum now: 1200/troy oz, 12/lb). I think newer ones use a lot less and also use palladium, which is a a lot cheaper.

Yes, I owned a recycling company for a few years, and used to pay as much as $150.oo for the big G.M. cats. The newer ones weren't worth as much though because they changed the design, and materials they were made of.

truckinik · #13 03-04-2007, 05:48 PM

Quote:

Originally Posted by Strife

Supposedly, the original mid 70's cat converters used quite a bit of platinum and were definitely worth recycling for the platinum content (platinum now: 1200/troy oz, 12/lb). I think newer ones use a lot less and also use palladium, which is a a lot cheaper.

Nice SL, by the way.