Zinc

[Rust_Belt_Pete]

Hey folks, my old Moto Guzzi needed to have high zinc oil due to tappets lifters or some such valve related stuff.
I was browsing subaru forums and heard people talking about how subaru boxer engine could use the zinc too.
I think zinc amount in oil was reduced due to emissions and or harm to catalytic converter?
What will extra zinc do to a modern engine?

 

[kschachn]

Zinc doesn’t harm a converter, it’s phosphorus that does. And it has to get there first so it’s entirely related to your consumption.

 

[OVERKILL]

Zinc doesn’t harm a converter, it’s phosphorus that does. And it has to get there first so it’s entirely related to your consumption.

Yup, and zinc doesn't provide the AW function either, that's also phosphorous, the zinc is just there to neutralize it.