One More Timing Question
 

It's been a long time since I have set the timing on a car so have one question. From what I have read the initial timing is set with the car in Drive at 600rpm,vacuum advance disconnected and line plugged, is that correct?

Hello fellow FF. When I set the timing I do disconnect and plug the vac advance, but I leave it in park. When setting the idle, I do that in drive to the RPM I'm looking for. Hope that helps...
Jeff

Do you set your idle rpm before or after the timing?

I set the idle to about what it should be, while it's in park 6-800 rpm. That is just a starting point because the idle speed will change when you set the timing. Then set the timing. Once you are happy there, set the idle. Then I check the timing again to to double check.

Hope that makes sense.

Jeff

Maybe someone here should educate me on Manifold and ported vacuum. In the pictures you can see the vacuum sources I have available. Right now, the distributor is hooked to the port on the carb. Car idles smoothly, goes into gear easily and the tranny shifts smoothly. But, there is no difference in rpms when I hook the vacuum to this port.
Initial timing is at 12 degrees.
When I hook the vacuum line to the port on the intake manifold the car idles rough, goes into gear hard and shifts hard.
The only other vacuum sources on the carb are the one that the transmission is hooked to and the brake booster port on the back of the carb.

Check out this link. Good info.


http://www.corvetteactioncenter.com/...m-advance.html

I set the timing first, then the idle, as the idle speed will vary a bit.
The vacuum source for the dizzy, should not be a constant pull. Now, different carbs have different ports. Mine is a tripower....
I have fine tuned the timing with a vacuum gauge, with a constant pull...manifold vacuum.
Every engine is a bit different, cam, trans, etc.
Remember to plug the hose and the port, then set your timing, then reset the idle speed. Then fine tune it.
Custom curved the dizzy?

You can purchase from PY a carb bolt that secures the carb to the intake manifold, which has a rod that runs thru it and gives you another source for manifold vacuum. I use it on mine and installed on the driver side rear location on the carb spacer. I have my vacuum advance canister hooked up to it.