Help setting timing and vac advance
303.
You start with idle timing....& finish with the WOT curve.
This is how you do it, & in this order:
- with approx 10-16* init timing, carb idle adjusted as best as you can, engine idling in gear if auto slowly turn dist to advance timing; turn until you get the highest rpm; toggle dist to make sure you have the highest rpm. Then check the timing.....This part of the test is now finished.
- say you got 40* in the test. That is what THIS engine needs for best idle, highest vacuum etc. It can be any combination of init [ static ] + MVA that gives 40*. Some of the Chrys dists only get 22* from the VA unit. GM HEI units give about 30*. A 440 I dialled in some months ago reqd me to adapt the GM VA unit to the Chry dist to get enough MVA at idle.
- so now you know the idle timing reqd, select the combination of init + MVA. Always better to keep the init low & use as much MVA as possible; it reduces the possibility of light throttle pinging.
- now you select the total timing for WOT. If you, say, selected 18* init & want 38* at WOT, then the centri curve needs t be 20*. The actual combination of springs/weights would be any bodies guess & getting that dialled for max HP at various rpm levels could only be found on a dyno.
- if you get light throttle pinging......idling in gear, turn AS 2 turns CCW & check timing. Keep going 2 turns CCW, checking timing each time, until timing moves or becomes unsteady. Then turn AS 3 turns CW.
303.
You start with idle timing....& finish with the WOT curve.
This is how you do it, & in this order:
- with approx 10-16* init timing, carb idle adjusted as best as you can, engine idling in gear if auto slowly turn dist to advance timing; turn until you get the highest rpm; toggle dist to make sure you have the highest rpm. Then check the timing.....This part of the test is now finished.
- say you got 40* in the test. That is what THIS engine needs for best idle, highest vacuum etc. It can be any combination of init [ static ] + MVA that gives 40*. Some of the Chrys dists only get 22* from the VA unit. GM HEI units give about 30*. A 440 I dialled in some months ago reqd me to adapt the GM VA unit to the Chry dist to get enough MVA at idle.
- so now you know the idle timing reqd, select the combination of init + MVA. Always better to keep the init low & use as much MVA as possible; it reduces the possibility of light throttle pinging.
- now you select the total timing for WOT. If you, say, selected 18* init & want 38* at WOT, then the centri curve needs t be 20*. The actual combination of springs/weights would be any bodies guess & getting that dialled for max HP at various rpm levels could only be found on a dyno.
- if you get light throttle pinging......idling in gear, turn AS 2 turns CCW & check timing. Keep going 2 turns CCW, checking timing each time, until timing moves or becomes unsteady. Then turn AS 3 turns CW.