Any harm to vintage engines running unleaded fuels. Options

[914043]

Back in the day when they took lead out of gas there was a lot of concern that without the cushioning effect the lead had on the valve face there would be bent and broken valves. Since my car fits those criteria and will be driving soon what if any concerns should I be aware of?? Fairly technical but Thanks for any help that might save me a damaged engine. Best to Ya

[bbrock]

From what I have read, all Porsche engines since at least the 60s had hardened seats so will do fine with unleaded gas - at least from what I've been able to find online. I'm sure someone else can verify or refute that. VW-Porsche magazine had an article where they tested the hardness of Type IV valve seats. They might have tested others but it was a long time ago and I was only interested in Type IV at the time. The upshot was that the factory seats were plenty hard to run unleaded without problems so I'm very confident we don't need lead additives in our 4 bangers. Also, if valve seats have been replace on any engine as part of a rebuild since the 70s, they will be hardened seats, so no need to worry about lead additives.

This is a topic where facts get buried under opinion which always attracts me to learn more. Here's what I've gleaned:

Lead was originally added as an octane booster. The lubrication properties were a side benefit. The most important was that a layer of soft lead would build up on the valve seats and cushion the impact of valves as they closed. Some manufacturers took advantage of this by using softer seats. As for other lubrication properties, modern fuels also have them, but with non-lead additives. Finally, what usually gets overlooked is the corrosive properties of lead in an engine. It seems lead may have done more damage to engines than the benefits.

We also shouldn't confuse the effects of lead as a lubricant and its effects as an octane booster. The latter is a whole other topic where anecdote and opinion seems to swamp fact.