Dick,
------------Snipped a bunch----------------
Gary---My reply here as to the issue of ignition timing at idle falls
close to Terry's corner. This is my understanding:
"Anyway, with the thermal switch interrupting the vacuum retard, two
things happen. The engine speeds up due to the advancing of the ignition
timing. This promotes better cooling because of a corresponding speedup
of the water pump and fan, plus better engine efficiency. (How can an
engine run efficiently when the spark event is After TDC?)"
Again here I have no formal knowledge just a shade tree mentality. If the
"bang" comes before the piston gets to the top of stroke(TDC) then some of
the energy is going to be used up in trying to push the piston backwards
rather than the direction we want. With it advanced the bang happens after
the piston is past the top so all of the explosion pushes it down. I guess
theoretical best place would be to keep the bang as close to, but after TDC
as possible.
I wonder if the heating at retarded spark comes from the energy loss(waste)
caused by having to force engine rotation against the bang caused by the
10deg BTDC spark.
Steve
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