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This is a myth. Lead has no lubricative value in engines, and in fact causes damage. From https://www.shell.com/business-customers/aviation/aeroshell/knowledg
by nate_meurer 5y ago
This is a myth. Lead has no lubricative value in engines, and in fact causes damage. From https://www.shell.com/business-customers/aviation/aeroshell/knowledge-centre/technical-talk/techart-18-30071600.html https://www.shell.com/business-customers/aviation/aeroshell/...:
"The temperature for Lead deposits to form tend to be favourable around the spark plugs (as the whole mixture is quite cool before the flame starts to propagate) and on the exhaust valve stem (as the mixture cools after combustion). The problem is that the deposits are electrically conductive, which shorts out the spark plug - and corrosive, which can start to attack the metal of the valve stems."
- jabl 5y agoLate in WWII very high octane 115/145 aviation gasoline (read: lots and lots of TEL) became available for Allied frontline fighters, giving a performance boost. When cruising, pilots had to periodically rush the engines to full power in order to burn off the lead deposits on the spark plugs. And the spark plugs had to be replaced after every flight.
- nate_meurer 5y agoWow, I didn't know that. The engine in my favorite airplane (Fairchild P-47) had 36 spark plugs. That's a hell of a maintenance requirement.