Catalytic Converter Problem?

JTG said
Syleng1, not a silly question, I'd be asking the same thing. I'm a double lung transplant recipient, had the cats installed to help lessen the fumes for health reasons, wasn't an easy decision to make at the time to have these installed on a car that would never have them in the first place, there the high flow ones so not very large in size, but they did lessen the fume smell dramatically, way more then what I ever expected.

Okay- that is a really good reason. You are lucky to be here and taking precautions are good to protect your gift.

So honestly- running cats on cars not designed for them is no easy feat. Maybe investing in a fuel injection system or a power train that runs a lot cleaner to begin with is a better choice. You see the raw fuel on decel with a carb can load up in the cat and then when you accel it burns so hot and fast it can damage the cats. A fuel injected vehicle controls this process like a thousand times a minute to maintain the perfect (well sort of) exhaust burn. Also protecting the cat. The way the cat works is it absorbs oxygen to help “reburn “ the exhaust flow but needs the cycle of oxygen storage and then release, oxygen storage and release. With out that flow the cats will be damaged.
So there is not one cat that can easily handle this without the oxygen flow. Early GM cats were removable pellets (balls) that could be replaced - trust me I did my fair share as a gm tech in the 80’s. They would melt together and became a clog because of feed back carbs not being able to control the oxygen flow properly so they added o2 pumps or air pumps to engine to help add oxygen to the exhaust stream to supply the cats with enough oxygen flow. All of that with carbs. The first fuel injection set ups for emissions reasons helped but wide open throttle still created cat overheating due to the lack of O2 in the exhaust stream.

Anyhow- all I am saying is your engine is causing the damage because it was not designed to handle what the cats need. So change the system (aftermarket fuel injecting, modern motor, or add an air pump system like off a late 80’s van ) to protect the cats. Otherwise uncontrollable rich and lean conditions will cook the cats very quickly. I also want to add that the info I am giving is over 35 years old from my head. Go and start looking up info on engine carbureted with cats from the 80’s. You will find better more detailed info than what I remember from that time frame of my life. Look up How a cat works first to understand what you are dealing with. You may have a lean condition (too little fuel) so there is lots of oxygen in your exhaust stream or too little Oxy from a rich condition. The cat needs the cycle of rich to lean back and forth to work properly.