I was under the impression thar’s what the mid-grade petrol was for; it had a high-enough octane factor to be non-knocking in engines designed for leaded.
It wasn’t in fuel just for it’s octane boost. Some early engines that were designed to run on leaded fuel had valve seats made of softer metal and relied on lead’s lubricating/sealing properties. When unleaded fuel was used, the valves wouldn’t seal as well and the seats would wear prematurely.
I was under the impression thar’s what the mid-grade petrol was for; it had a high-enough octane factor to be non-knocking in engines designed for leaded.
It wasn’t in fuel just for it’s octane boost. Some early engines that were designed to run on leaded fuel had valve seats made of softer metal and relied on lead’s lubricating/sealing properties. When unleaded fuel was used, the valves wouldn’t seal as well and the seats would wear prematurely.