Quote:
Originally Posted by crazyhorse
The valves would burn due to the increased combustion temps and pressures that the higher octane brings. (Because of the slow burn) Add in the fact that the old US stuff didn't have hardened valve seats, and you have a recipe for destruction.
The other thing to remember is that back then "regular" was 110 octane.
AvGas could have been upwards of 200 octane! 
Modern AvGas is 100-130 octane, depending on air/fuel mixture. It's not rated the same, so a direct compairison is difficult. The older chemistry was rated the same as today's pump gas. |
A change of octane doesn't increase "combustion chamber pressure or temps."
They did not need harden valve seats, they used Tetra ethel lead to lube them and raise the octane.
Back then the octane was about 85, 200,,,,,,,,,
still havent got there yet..
The chemistry remains the same, we just have two system to rate it Mon and Ron.
Harvey.