It’s no secret that older engines aren’t like today’s modern computer-controlled powerplants. In particular, high-performance older engines (like those in classic cars and hot rods) have lubrication demands that are not met by modern oils.
That demand, in a word, is zinc dialkyldithiophosphate, otherwise known as ZDDP. We’ll come back to that in a second.
But first, why are modern oils lacking ZDDP protection?
It’s a simple story of market evolution: over the years, motor oils have been updated to meet the needs to changing engine designs. While that’s great for newer motors, it leaves older engines out in the cold. These updated oils have greatly reduced ZDDP levels, so they simply do not offer the protection needed for older engines.
So then. What is ZDDP anyway, and…