Cleaning Catalytic Converters?

[dwcopple]

Originally Posted By: TFB1

LOL, Scotty is a sharp dude, if he says cleaning works I believe him...

He also says the Head Gasket stop leak in a can works too though...

 

[DriveHard]

I have to say I am surprised nobody has offered this solution yet. I would think the best, and by far easiest way to really heat up the exhaust is to get it on the highway, and run in the lowest gear you can for about 10 miles or so. I would run it 500 to 1000 rpm shy of the redline for about 10 minutes...promise you that will heat up the cat!

 

[lexus114]

Originally Posted By: DriveHard

I have to say I am surprised nobody has offered this solution yet. I would think the best, and by far easiest way to really heat up the exhaust is to get it on the highway, and run in the lowest gear you can for about 10 miles or so. I would run it 500 to 1000 rpm shy of the redline for about 10 minutes...promise you that will heat up the cat!

Yeah that would probably do it alright, but you would have other problems afterward as well.

 

[DriveHard]

Originally Posted By: lexus114

Originally Posted By: DriveHard

I have to say I am surprised nobody has offered this solution yet. I would think the best, and by far easiest way to really heat up the exhaust is to get it on the highway, and run in the lowest gear you can for about 10 miles or so. I would run it 500 to 1000 rpm shy of the redline for about 10 minutes...promise you that will heat up the cat!

Yeah that would probably do it alright, but you would have other problems afterward as well.

Like what? I do this once a year on my 10 mile drive home from work with my cars. I have never had any problems doing this on any of my cars...at all. What problems would you think would happen?

 

[Vikas]

The bigger question is, what problems did that solve? How do you know that you had that problem to begin with and that it was solved by the specific method?

 

[ProStreetCamaro]

Best way to clean a catalytic converter is to cut it off, hammer out the center then weld it back on. There problem solved and you free up some power.

 

[lexus114]

Originally Posted By: ProStreetCamaro

Best way to clean a catalytic converter is to cut it off, hammer out the center then weld it back on. There problem solved and you free up some power.

Hahaha!!

 

[DriveHard]

I am not solving any specific problem with this method...I was supplying it as a possible solution to cleaning out the Cat. I do it later in the Iowa winter because I know my engine goes a long time without getting good and hot during the winter. I know that the exhaust gets VERY hot during this trip, so I assume it would be a good method to melt things out of the cat. I just don't see how this would be bad at all on my car as long as it was warmed up before I hit these higher engine speeds.

 

[ProStreetCamaro]

Originally Posted By: lexus114

Originally Posted By: ProStreetCamaro

Best way to clean a catalytic converter is to cut it off, hammer out the center then weld it back on. There problem solved and you free up some power.

Hahaha!!

I have actually done it. Did it to my very first car. It was an 82 Z28 with a ZZ4 crate motor, long tube headers, TH350 trans etc etc. Left the smog pump unhooked and it burned up the converter and it got so clogged it would barely run and was spitting gas back up through to carb. To pass emissions I simply ran it almost empty and dumped a bunch of alcohol in the tank. Ran a little rough but it passed the sniffer. Went straight up to the gas station and filled it up to dilute the alcohol.

 

[BrianWC]

Careful on heating up the cat. When one of the coil in my saab 900's direct ignition pack went out and caused a misfire that dumped a bunch of unburnt gas into the exhaust, I ended up streaming molten cat converter parts out my tail pipe for a few miles. Quite a sight at 5 am.

 

[JTK]

Once the magic stops happening in an automotive CC, there's no 'regenerating' it. The substrate isn't built to handle a re-fire, nor is the small amount of precious metals plated onto the substrate. Once it's soured, it's soured. Joel

 

[artificialist]

Originally Posted By: BrianWC

Careful on heating up the cat. When one of the coil in my saab 900's direct ignition pack went out and caused a misfire that dumped a bunch of unburnt gas into the exhaust, I ended up streaming molten cat converter parts out my tail pipe for a few miles. Quite a sight at 5 am.

A similar thing happened to my dad's 1979 Toyota Corolla. After that happened, he was always afraid to drive over grass, fearing that the car would light the grass on fine. I think the problem that led to catalyst meltdown was not related to spark, as the engine was running fine right before it happened. I heard that it was because Toyota A.I.R. pumps and check valves were a common problem that led to catalyst meltdown.

 

[rationull]

Originally Posted By: TFB1

That ain't happnin', because few vehicles of the last 15 years even have a distributor... If they are crank triggered as the OP mentioned his is, moving the distributor only changes the position of the cap tower in relation to the rotor... Makes no change in timing at all...

I'm having trouble imagining how, on any vehicle with a distributor, the timing could NOT be affected by rotating the distributor cap/housing. Unless you're saying that in such a setup the distributor rotor is moved by an electric motor or some other infinitely variable drive instead of a gear on the crank/cam/oil pump or whatever. It is "the position of the cap tower in relation to the rotor" that defines the timing, assuming the rotor is mechanically driven by something connected to the main rotating assembly in the engine. What am I missing?

 

[yonyon]

Originally Posted By: rationull

Originally Posted By: TFB1

That ain't happnin', because few vehicles of the last 15 years even have a distributor... If they are crank triggered as the OP mentioned his is, moving the distributor only changes the position of the cap tower in relation to the rotor... Makes no change in timing at all...

I'm having trouble imagining how, on any vehicle with a distributor, the timing could NOT be affected by rotating the distributor cap/housing. Unless you're saying that in such a setup the distributor rotor is moved by an electric motor or some other infinitely variable drive instead of a gear on the crank/cam/oil pump or whatever. It is "the position of the cap tower in relation to the rotor" that defines the timing, assuming the rotor is mechanically driven by something connected to the main rotating assembly in the engine. What am I missing?

You misunderstand how base ignition timing adjustment via rotation of the distributor works. With the older mechanical style 'breaker-points' triggered ignition, turning the distributor moves the cam follower (mounted to the dristributor base -- moves when distributor is turned) relative to the cam (mounted to the rotating shaft of the distributor -- moves as the engine cranks). Traditional electronic ignition is a similar scenario but with an electronic 'ignition pickup' or crankshaft position sensor which is usually a hall effect switch or variable reluctor type sensor mounted to the distributor and a trigger wheel wheel or toothed wheel mounted to the distributor shaft. With an optical distributor it's again the same thing with moving the sensor/pickup attached to the distributor relative to a trigger weel (disc with holed in it) attached to the distributor shaft. Turning the cap won't change timing except that if you move it far enough the wrong contact will be closest to the rotor tip at the moment the spark event is initiated and at that point you'll change the firing order. For distributor type ignition systems that rely on an external (not inside distributor) crankshaft position sensor, rotating the distributor will have zero effect on timing unless the distributor is turned far enough to shift the firing order.

 

[rationull]

Originally Posted By: yonyon

You misunderstand how base ignition timing adjustment via rotation of the distributor works. With the older mechanical style 'breaker-points' triggered ignition, turning the distributor moves the cam follower (mounted to the dristributor base -- moves when distributor is turned) relative to the cam (mounted to the rotating shaft of the distributor -- moves as the engine cranks). Traditional electronic ignition is a similar scenario but with an electronic 'ignition pickup' or crankshaft position sensor which is usually a hall effect switch or variable reluctor type sensor mounted to the distributor and a trigger wheel wheel or toothed wheel mounted to the distributor shaft. With an optical distributor it's again the same thing with moving the sensor/pickup attached to the distributor relative to a trigger weel (disc with holed in it) attached to the distributor shaft. Turning the cap won't change timing except that if you move it far enough the wrong contact will be closest to the rotor tip at the moment the spark event is initiated and at that point you'll change the firing order. For distributor type ignition systems that rely on an external (not inside distributor) crankshaft position sensor, rotating the distributor will have zero effect on timing unless the distributor is turned far enough to shift the firing order.

OK, based on that description I think maybe I did have the basic concepts more or less correct, but the piece I was missing is it sounds like the rotor tip does not have to *touch* the contacts on the cap in order to fire -- just has to be closest to the correct one and the spark (which is controlled by the CPS or whatever takes its place) will jump the gap. Right?

 

[IndyIan]

Originally Posted By: Loobed

I was reading somewhere (?) that it is possible to clean a catalytic converter (cat) by getting it hot enough to boil off any metallic contaminants. Lead is not a problem because there isn't any lead in gasoline. Zinc and Phosphorus contaminants are what I would like to remove. A modern cat's running temperature is 1200 to 1600 *F. Phosphorus boils at under 600*F, and Zinc boils at under 1700*F. Both of those boiling points are for the substance in their elemental state; In compound form (ZDDP) them may have a higher boiling point. Does anyone know what I could do, or maybe add to gasoline, to raise the temperature of the cats, temporarily, above 1700*F? I know running the engine hard under load can do it, but I don't have an area (open highway) available where I can do that. I read that increased amounts of fuel in the exhaust can cause the cats to get very hot (and melt). I was wondering if I could set up a propane torch, not lit, near my smog air pump inlet, and then turn on the air pump manually to pump unburnt propane into the exhaust system and into the cats? Propane seems like the cleanest fuel to add to the exhaust. will Acetone, MEK, Toluene, or some other chemical added to the gasoline make the cats run hotter?

My Tracker failed an E-test, so before the retest I took it out on the highway and just hit the throttle WO from 45-60mph about 2 dozen times in top gear. WO makes the ECU go into "open loop" mode which pulls some timing and goes rich so the cats will see more gas and heat up converting it. After that "treatment" the car passed the retest easily. I now do this before every E-test and even my Neon passes easily.