Vacuum Advance - where do you have it set?

[RG801]

Hi,

Where do you guys have your vacuum advance set? I've got my base timing set at 10* and have been experimenting with the advance adjustment. I've read that you shouldn't go above 36* at 2000 rpm, which seems high to me. What has worked for you?

 

[Broncobowsher]

Never measured it. But I set the last one just a shy of detonation at cruise.

 

[broncnaz]

The vacuum advance is there to make up for slow mechanical advance and helps driveabilty and emssions. Basically as long as your engine is not pinging you can run as much as possible. Its not uncommon for engines with vacuum advance to see timing advance to 40-50 degrees again as long as theres no pinging your fine. Your first thing to do is run the engine with the vacuum advance unhooked and make sure theres no pinging. Once thats verified then run with the vacuum advance hooked up if you get pinging then you can try adjusting the vacuum advance. just stick either a 3/32 or 1/8" allen wrench into the vacuum nipple then turn 2 turns counter clock wise and retest. if you still get pinging. keep adjusting and testing as before until there is no more pinging.

 

[Explorer]

The last Duraspark I curved, I set to 32-34 total advance and all in at 3000rpm. That worked well for the bone stock 302.

 

[Ranchtruck]

The vacuum advance would cause a stumble at initial throttle tip in for me, so I just tightened it up until that stumble was minimized. Vacuum advance is there for fuel economy, so I'm not too concerned about how "right" it's set.