[net.misc] Regular vs Unleaded Gas

jrc (02/10/83)

I have heard from several independent sources that leaded
("regular") gas is actually better for your engine, if you
can use it.  The theory states that lead, being a very soft
metal, makes an excellent lubricant when heated to engine
temperature.  Thus the life of your engine can be significantly
extended by using regular gas.  This effect should be particularly
noticeable in motorcycles, whose engines are run at much higher
rpm's than most automobiles.

My social conscience led me to begin using unleaded gas in
my Honda Accord, but my mechanic told me I was crazy to do it,
so I stopped.

Jim Cordy
University of Toronto

dmmartindale (02/11/83)

There is no metallic lead in "leaded" gasoline.  The octane-increasing
additive is tetraethyl lead.  I don't know what it turns into during
combustion, but I would expect a lead oxide of some sort.  Whatever it is,
it tends to deposit on things, and provides lubrication for the valves
and valve seats.  Older engines need this; newer ones use better materials
in the valves and seats and can withstand running with no help from the lead
byproducts.  Presumably they will still last longer if the lead is around.
It can be a mixed blessing, though - lead deposits on the valve stems
can cut down gas flow through the engine, and sparkplugs can become
lead-fouled (a very common occurrence in aircraft burning 100/130 octane
fuel, which has lots of lead in it).

hennessy (02/13/83)

#R:watcgl:-18500:uiucdcs:10600057:000:101
uiucdcs!hennessy    Feb 12 17:51:00 1983

Another reason tetraethyl lead was used in gasoline was
to increase the octane number.

Rob Hennessy