TOTAL ignition timing question

[NormD]

302 with vaccum advance distributor.
Should the vacuum line to the distributor be connected or disconnected when doing "TOTAL" ignition timing. Initial ignition timing I know is done with vacuum line disconnected and for me it's 15 degrees. I understand "TOTAL" ignition timing should be around 32 degrees. any help explaining how to do TOTAL ignition timing will be appreciated. tks Norm

 

[enferno]

it jsut depends on how many degrees of advancement your dizzy gives you

 

[brianj5600]

To check total, you leave the vacuum unhooked and rev the motor while checking the timing. If you have a helper it is easier. Increase revs until the timing peaks. That will be your total. Be careful setting initial and assuming total. My duraspark distributer had 36* of mechanical advance. I welded the windows up and ground one for 20* and the other for 18*. I have seen a couple threads were people suggested intial setting w/o knowing mechanical advance. If I set my original distributer at 15*. I would have had 51* total.

 

[fasttback]

Plug vacuum line when setting timing.

Initial and total settings will depend on your motor, heads, cam and gas you can run (among other things). Testing YOUR vehicle under "typical driving conditions" is the only way to fine tune it. Everyones motor is different.

Here are some ballpark numbers: typically our performance engines will be set between 10-18 initial with 32-40 total. The timing curve is another thing to consider. I would focus more on your total timing and it should be maxed out around 3000 rpm.

 

[NormD]

Thanks, I will give it a go!