I've been doing some more research and thinking into the ignition timing effects of 'late' timing and how that might effect engine temperature, just because that sort of thing interests me, not that it will be meaningful with the current engine situation.
However, it looks like given a certain amount of energy delivered to the cylinder of an engine, in the form of fuel that is burned during the combustion cycle, the energy is released as a combination of mechanical work and heat. If the ignition of the fuel is too late in the cycle, the burning fuel will not have as much opportunity to perform 'work' upon the piston, since the piston would be further along in its downward movement. Less work done on the piston, means more heat left in the combustion gases, resulting in a hotter engine.
This is all theoretical of course
I would think that the timing would have to be off by a considerable amount to really have a measureable effect though . . .
Game plan for Saturday is:
- Cooler of beer (gonna be sunny and hot)
- Change Rotors and Distributor Caps on both engines
- Set each engine into base timing mode and check timing.
- Test engine temperatures
- Check spark advance consistency at idle speeds using the Diacom software
- Test the IAC valves using the Diacom
- Change IAC's if needed
- Check Fuel Rail Pressure, if ignition timing and IAC do not resolve issue
- I was also thinking about checking the exhaust tubes to see the condition of the flappers.
- Check compression to see if any evidence of exhaust valve deterioration
- Use inspection camera to visually check the exhaust valves (I got a new camera with the smaller 7 mm head so I should be able to get a decent view of the valves)
