lead and octane - longish

[JMNegrin@xxxxxxx]

My understanding is that tetra-ethyl lead (a lead-containing, carbon compund)
was added to gasoline as a cheap way to improve the anti-knock properties of
lower grade fuel, i.e. to raise the octane rating.  The result of all
additives, and their effects on pinging, detonation, or
whateveryouwanttocallit, resulted in an emperical index referred to Research
Octane.  

100 percent pure iso-octane (a configuration of an 8-carbon hydrocarbon chain
particulary good at resisting pinging) had the Research Octance Number (RON)
of 100.  It is possible to achieve better anti-detonation than pure iso-
octane, so it was/is possible to get research octane numbers higher than 100.
(Race gas is 110 - 116, and pure alcohol is about 160!)  The octane number is
only there as an indicator of anti-knock properties.  Nothing else.

The other octane number we may be familiar with is the Motor Octane number.
This relates more to the way the motor actually runs, and not a theoretical
value.  In California, just to make things more interesting, we have on the
pump, the average of both the research and motor octane values R+O/2.  Premium
is typically 92 and rot-gut is 88.  

If I remember correctly, Chevron White Pump, back in the sixties was rated at
about 102 RON, a bit higher than most commercially available pump gas.  I also
seem to remember that most/all pump gas was labelled with RON, not Motor
Octane, or an average.

I also thought that after all was said and done in the combustion chamber,
lead was released as elemental, and formed a light coating on the valve and
seat.  This was more of a cushion than a lubricant.

More??

Not now

Jay Negrin
ARO Southern California
76 Alfetta GT

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