-Good old fashioned Regular had TEL, Tetra ethyl lead, which also lubricated
the valve seats. Newer cars, post 73/74 have hardened steel valve seats,
being aluminum heads, the datsun seats must be bronze or steel. My old
Dodge 340 used to burn the exhaust valve seats so badly you could see the
difference in valve stem height at the rocker arms from the valves receeding
into the seats after a while. Could have been the 7400 rpm runs? (Witnesses
and sworn affidavits available : )Not too bad for a stock bottom end with
hydraulic lifters. Changed to late model heads with higher compression even,
and problem went away.
I'm told that Marvel Mystery Oil added to the gas may help, can't hurt and
it's cheap. I'm going to use it, have a can lying around somewhere, next to
the jar of antiseize compound that never seems to run out, had it for years,
use it all the time, but it's always 90% empty, must regenerate or something
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