Cracked Catalytic Converter

So this is a magnaflow CA legal cat that I had on my truck for a few years before I had issues with my O2 sensors. New denso sensors and cat later and no codes so I'm good on that. I have had my old magnaflow sitting in my backyard for a while and I just noticed that it has a crack. Can these be patched up and welded? or is this junk now? I wanted to sell it for cheap,but knowing about the crack now is it junk? I don't want to screw anyone over. It doesn't rattle at all either. Would anyone even want a Cat with a crack in it. I know these are expensive parts.

 

I could be wrong but it looks like the crack isn't technically on the converter itself but on the piping just after it, I don't see why that couldn't be patched up and/or welded over.

 

I was thinking the same thing but I wasn't too sure.

 

As long as there isn't a bunch of rattle noises in the cat like if it cracked from getting dropped or smacked with something that might have damaged the material inside. If you hear rattling in it then the material is coming loose. Could still be good for awhile but would have to price accordingly

Don't know if maybe you can shine a light into and see if you can make out how the material inside looks

I've been running CA approved Magnaflows front/rear for a few years now and they've been great, passed smog with 'em twice so far.

 

I'm no expert on cats but I'd say it's worth something to someone that wouldn't mind patching that crack

 

Thanks for the input!

 

Weld it and send it

 

I’ve seen a new videos on soaking them in some type of solution to clean all that gunk out on the inside. I’m eventually going with oem new ones but they ain’t cheap. I bought the Magnaflow ones and the fwd wouldn’t fit on my truck

 

Yep vee out the crack weld it up .

I wonder what caused the crack ?? poor support and vibration ?

 

Exactly my thoughts. nothing wrong with welding it up, but for sure you wanna make sure you're welding clean metal and not the rust and mud thats living on the inside of the crack.

 

I suggest TIG or gas weld.

 

It looks like fatigue related crack from heat cycles and constant vibration at just the wrong frequency.. love to hate resonance. We test a lot of automotive exhaust systems at work and shake them around with lots of heat to determine if components can hold up or blow up. Fix'r up, maybe weld some random bits and pieces on it to increase the mass or support it better lol

 

Why??

I doubt you could get things clean enough for a good Tig weld.

I can`t recall the last time I even Brazed anything let alone welded

 

Better heat control. Add to that, that metal gets hot and could be very thin. Definitely don’t want to disturb the precious metals inside.

 

I would recommend TIG welding for the purpose of controlling the heat affected zone since it is some grade of stainless, probably 321. IMO, a 1/16" ER312 filler rod with 2% thoriated tungsten electrode will work just fine. You should be able to get full penetration with less than 50A, but I cant tell just how thin the metal is. For best results backpurge the inside of the cat with 100% argon. For something like this I would make my purge dams out of masking tape or something like that, nothing fancy. Happy welding!