Quote:
Originally Posted by deuce_roadster
The main reasons for the removal or reductions of the heavy metals is that the older engines with flat tappet cams needed (mainly lead in the gas) for the valve seats and zinc for lifter bottoms. Now, valve seats are hardened and as far as I know all car engines have roller lifters which do not need the zinc. There are environmental reasons too.
|
That and catalytic converters are adversely affected.