Cams, Catalytic converters, ZDDP

[elacruze]

With all the talk of cam damage, ZDDP, and catalytic converters lately I did just a little research, to be sure I understood exactly how converters work; I knew there were two types but didn't know the difference. Anyway, what I found was very interesting on a number of fronts. I thought that ZDDP was removed from oil to reduce emissions, but didn't know that it affect emissions by disabling the catalytic converter;

From http://en.wikipedia.org/wiki/Catalytic_converter

'Poisoning-

Catalyst poisoning occurs when the catalytic converter is exposed to exhaust containing substances that coat the working surfaces, encapsulating the catalyst so that it cannot contact and treat the exhaust. The most notable contaminant is lead, so vehicles equipped with catalytic converters can only be run on unleaded gasoline. Other common catalyst poisons include manganese primarily from the gasoline additive MMT, and silicone which can enter the exhaust stream if the engine has a leak allowing coolant into the combustion chamber. Phosphorus is another catalyst contaminant. Although phosphorus is no longer used in gasoline, it (and zinc, another low-level catalyst contaminant) was until recently widely used in engine oil antiwear additives such as ZDDP. Beginning in 2006, a rapid phaseout of ZDDP in engine oils was begun.'