LEAD AS A LUBRICANT?
I have excitedly watched the developing story on the rollout of G100UL as a drop-in replacement for 100LL. It’s completely fungible with 100LL; no more lead in the exhaust, longer lasting engines/oil/spark plugs and reduced maintenance (never mind the one downside: price increase). Everything seems to indicate that the testing has been “extensive and comprehensive” as is described in the FAQs on GAMI’s website, and that there will be nothing but benefits to this drop-in replacement for 100LL.
However I can’t help but wonder if there was one flaw in testing. Nearly every engine on the market today has used 100LL since the 1970s. Therefore I imagine that all the engines used in testing (both on the stand and in a plane) had previously used leaded fuel, which acts as a solid lubricant. One engine component where this lead lubrication proved important was the valves and valve seats. When the auto industry removed lead from fuel, valves (and therefore engines) had a shortened life span due to the removal of the solid lubricant. This issue was eventually overcome with engineering (hardening the valve seats). This wasn’t a big deal in the auto industry where the average age of a car is 12 years. After one decade of pain, most cars on the road had been re-engineered to use unleaded fuel and therefore no longer have any issues.