Too much advance

[Scott Sinclair]

I have a 1970 440 4 bbl, it has a Mopar electronic distributor. I am getting 55 degrees of total advance with the vacuum pot hooked up. Does anyone know what part number the correct vacuum unit that I need.
Mopar newbie,
Thank you
Scott
scott1956@rogers.com

 

[Rodcuda]

Disconnect the vaccuum advance and set your timing to about 36 degess total advance without the vaccuum hooked up. Hook your vaccuum advance back up and you should be good to go.

 

[Meep-Meep]

That's exactly what I get with mine so at least they are consistent. My timing is set to 36-38 total with 16 deg of initial. If you are checking total timing in the driveway and the advance can is hooked up you should see the full 55 deg at say 2500 RPM. You need to unplug it and set total timing to 36 or so and reconnect it to the ported vacuum fitting. The idea is that under high load the throttle blade is well past the ported vacuum port and no longer receiving a vacuum signal so the timing snaps back to the mechanical setting. The only way to properly set the vacuum advance is to drive the car with a vacuum gauge teed into the ported port and get the reading while cruising under very light load - in other words barely into the throttle to maintain FWY speeds. Record the vac reading and apply it to the advance can to either increase or decrease the vacuum advance. I think 55 is a little high and plan to knock about 10 deg out if mine.