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It's known a cat can be burned by an engine running too rich for too long, but i wonder what the effects are of constantly running lean. Will the cat just be uneffective because of the lack of CO, or will permanent damage be done to it? Would you please be so kind to refer to the source if you have any information about this, thanks.
Cheers
A lean burn won't necessarily ruin your catalytic converter. What it may do long before that happens (depending on how lean you're running) is burn the exhaust valves, piston crowns and overheat your engine. Fuel as much as being required to cause ignition also provides a crucial role in cooling the piston, cylinder and exhaust valves.
What damages the catalytic converter is the heat of reacting unburned fuel. So a lean or stoichiometric mixture should do no damage at all.
