"I'd like an answer to this, too. I've forgotten what little I knew
about cetane and octane and diesel and gasoline...octane being the
ability to detonate, and cetane the resistance to detonate, and
therefore a lower octane detonates more easily than a high octane?"

Octane rating is defined as the resistance to detonation of a fuel in
a SPARK IGNITION engine. That may not be the rigorous definition, but
it's pretty close.

I'm uncertain about cetane rating, other than it is a measure of the
fitness of a a fuel for use in a COMPRESSION IGNITION engine.

Point being, cetane rating is meaningless in the context of a spark
ignition (gasoline) engine, and likewise octane rating is meaningless
in a Diesel.

"I do know the diesel works in hot weather in a gas car in small
quantities--and a V8 just seems to run cooler, but maybe that is just
me. I knew some diesel drivers back in Ontario/Quebec who reversed the
process in deep winter (say, -30 to -40 range) and added some gasoline
to the tank to improve ease of detonation."

Apparently adding a little Diesel fuel to you gasoline reduces the
incidence of vapor lock by lowering the vapor pressure of the fuel. I
suspect the truckers who added gasoline to their Diesel fuel did that
in order prevent the fuel from gelling, especially if they got caught
in a cold snap with summer fuel in the tanks. Could be a risky
business, though, as gasoline is such a poor lubricant, that the
injection pump could be damaged.

"Because diesel is a lot less "dry" than gasoline (especially ethanol
blends?) and provides more lubrication, I would think that it would
reduce the likelihood of detonation from spot overheating in a
high-pressure/high-compression and temperature V8 like an R4, and
aren't there more BTUs available in diesel over gasoline in any case?
(or is it a bad thing in an R4?)"

Jim Bartley

I don't know the octane rating of Diesel fuel, but it must be pretty
low. I've heard instances of people accidentally filling their
gasoline vehicle with Diesel, and thinking their engine had blown
because it was knocking so badly.

I don't think I'd risk putting Diesel fuel in an R4 engine.

Gord Richmond