Help! I've fallen behind and I can't catch up! I took a four day weekend
last week and I have been trying to catch up on my reading ever since.
Most should be greatful for this because it gives me more cause for
restraint in my list correspondence. I cannot resist commenting on two
threads however, no matter how stale.
Advancing and retarding the ignition does not effect how much heat is
generated per combustion cycle. You burn so much fuel, you get so much
heat. However, the conditions of the combustion cycle do effect where the
heat goes. Heat transfer from the cumbustion gasses to the surrounding
structure happens much faster under high pressure than under low pressure.
Proper ignition advance means that the heat of combustion is held in the
cylinder longer and under higher pressure. This allows more heat to be
trasferred to the combustion chamber, cylinder walls, and piston crown.
These areas are well cooled by the water jacket, the oil, and the next
incoming fuel air charge. Later ignition means that less heat transfer
occurs in the cylinder where it is supposed to and more occurs in the
exhaust system. This results in overheating of the exhaust valves, ports,
and manifold. The hotter ports cause localised boiling in the head and the
car overheats. You also feel that the heat is greater because the engine
compartment will be much warmer.
Advanced ignition will not usually cause an engine to overheat. It will
cause too much heat transfer to certain component such as piston crowns,
rings, and valves. This could cause premature failure of these components.
Also, the high pressure of detonation can cause mechanical damage itself.
Concerning flourescent trouble lights. I agree that they could be
wonderful but remember, they don't work when it is real cold. I once made
the mistake of installing flourescent lights in my garage and I had no
light all Winter. That's a lot of darkness here in Minnesota. For you
listers in whimpier states, though, I say go for it!
Regards,
Bill Eastman
61 MGA with disk wheels and no "wire envy"
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