unblock cat without external damage

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ozmatt, Jan 21, 2021.

  1. ozmatt

    ozmatt Active Member

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    Hi just wondering if anyone has successfully unblocked their cat and at the same time recovered all the precious metals, without actually cutting it open?

    I realise this practice is generally frowned upon for road use but its just an experiment on an old junker, CEL does not matter as it does not need to be road legal

    Cheers
     
    #1 ozmatt, Jan 21, 2021
    Last edited: Jan 21, 2021
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    It's not difficult to beat the honeycomb out of a prius cat. The easiest way to do it for a Prius would be to cut the pipe a few inches past the second cat and remove the cat section from the car. Now there's an opening at each end to allow breaking up the comb structure and pouring it out. It's very accessible. I've thought about doing it to an old cat just to get it analyzed to see exactly what % materials are in the Gen 2 models. Being financially responsible, I looked into how I would sell the removed honeycomb. That didn't go well. The problem you'll have is finding someone to purchase the comb material. No recyclers I've found will buy loose comb material once its separated from the housing, for any reasonable price. Could you get it analyzed and certified or something? Maybe, but if someone came up to you with a bag of material and some paperwork that said it was xxxxxx, would you buy it? Or would you just stick with buying OEM housings stamped EA6 and GD3 with undamaged honeycomb inside? The difference between getting $1150+ for a set of OEM cats and $35 for a bag of honeycomb was just to much for me.
     
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  3. ozmatt

    ozmatt Active Member

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    Hi TMR- .. thanks for the reply :)
    do you think all the comb would come out that way or only the middle section, like would the outer edges stay stuck inside? like a donut lol,, also do you think only the first comb layer (in first cat) will be blocked, or would the second layer be toast too? just removing the comb from flange end of cat 1 might be enough

    i had a blocked cat fail completely a few years back where it started to kind of whistle out the exhaust and the car suffered an extreme loss of power, i always told myself the ceramic stuff had fallen to bits but never got around to doing an autopsy and have now lost track of that particular cat so its too late, but i am thinking it would be best to remove the ceramic as well, or maybe i am wrong.. but i doubt any amount of beating bashing or proding around will loosen up that ceramic enough to get it all out

    almost every cat i see has blocked honeycomb to some point, and this car has around 570k km so it burns a bit of oil, it will re-block replacement cat pretty quickly

    im not actually sure what to expect to get for the material, but i did find one scrap guy that is willing to buy it from me once i get it out, the other option would be to list the bag of mesh mess on ebay lol

    to get it completely empty there may be no other option than cut a window in top of cat, depopulate it then weld window shut
     
  4. drone13

    drone13 Junior Member

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    @ozmatt If you're going to remove the catalyst substrate make sure you are well protected with a good respirator and hazmat type of suit. The substrate is very harmful to the respiratory system. It is not advised to try and destroy the substrate without carefully opening the outside shielding. The substrate will crumble and release lots of hazardous dust, which will get all over everything in the area. Here's a link to some info:

    Davis Recycling Inc :: Catalytic Converter Questions Answers : How much is Catalytic Converter worth? Cash: catalytic converter recycling prices..
     
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  5. ozmatt

    ozmatt Active Member

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    Hey Drone, okay got it! .. Glad you mentioned this, im funny over this sort of stuff so i will neatly cut a window in top of cat! (while wearing a covid mask lol) thanks very much
     
  6. drone13

    drone13 Junior Member

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    Not to harp, but a covid mask is not nearly good enough. The substrate is ceramic and ceramic dust will really hurt your lungs. The method of bonding the precious metals to the substrate, like palladium, is to use palladium salts. These salts are poisonous. You really need full hazmat gear like respirator and suit. I'm not trying to talk you out of it, but please be extremely careful.
     
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  7. TMR-JWAP

    TMR-JWAP Senior Member

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    Another option is to purchase a $120 after market and run it (or gut it if desired). Install it and sell off the OEM for $1200ish.....
     
  8. ozmatt

    ozmatt Active Member

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    TMR, I wish! .. here in Australia the blocked up oem is worth no more than scrap value!

    if it was not blocked it be worth 1000 ish
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    that's odd, because the scrap value is around 1150 here. Are the cats stamped EA6 and GD3?
     
  10. ozmatt

    ozmatt Active Member

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    yea mate they are, EA6 on one and GD3 on the other

    i sold a blocked cat for $50 a few years ago lol

    that just seems insane to me, now i wonder who will give me best price in Australia
     
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    find a catalytic converter recycler and get an online quote. I did this about 3 days ago and the quote was around 1130
     
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  12. ozmatt

    ozmatt Active Member

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    okay thanks i will get something decent before i consider messing with it, don't want to mess myself up!

    TMR - okay i will be on to it mate thanks very much, might just put a cheap high flow on it

    BTW is that price just for the first cat, or do you need to trade in the whole pipe to get that
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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  14. ozmatt

    ozmatt Active Member

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    wow! so it looks like EA6 is the first one which always blocks up, and least expensive but still your last quote was $425 that's still over $600AU

    pondering all of the ideas! lol
     
  15. pasadena_commut

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    Well, if the whole exhaust was pulled off the car one could put anything at all into the front end.

    If it is totally blocked a stream of very hot oxygen gas directed onto the clog, allowing a path back out the front to vent the products, would eventually burn off enough material to unblock it. It isn't pure oxygen, but I suspect that a hot air rework station (the kind used to solder/unsolder surface mounted semiconductor devices) might actually be able to do this (after first extending the outlet tube so that one's hand isn't burnt to a crisp). The air out of those goes up to about 500C, which is much higher than the ignition temperature for most carbon based fuels.

    If it isn't totally blocked a mix of oxygen and methane (or natural gas) should heat it up to operating temperature, then tweak the concentration of oxygen up to burn off all the carbon based gunk while keeping just enough methane to hold temperature. It should eventually unblock everything which is just dirty. But not any tubes which have collapsed. In theory.

    Would this be:

    Easy to set up?
    Safe?
    Cheap?
    Quick?

    No, no, no, and no.

    That's why they are replaced instead of repaired.
     
  16. ozmatt

    ozmatt Active Member

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    Thanks Pasadena i have decided to go with an ebay weld in cat so i can scrap the original

    Looks like the 2.5" in/out overall 10" is a common universal cat size for prius ?
     
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