With that advance it also holds right at 15# of vac at idle.

I was chasing a small internal carb vac leak from one of the carbs.

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC

 

My distributor is connected to timed spark vacuum port on my holley, which I disconnected when I ran the timing light. the full vacuum ports are plugged. I'm going to try setting it down to 12-14 degrees this weekend and see how that goes.

Old time mechanics use a vacuum gauge to set up timing.Disconnect vacuum hose.Advance the distributor slowly until maximium  reading on gauge,Turn it back slowly until vacuum reading starts to drop.Set the timing halfway between highest reading and where it starts to drop.Road test for ping under load.Back off timing slowly until it doesn't.

  

Thanks for the tip Mark. I'll try and get a hold of a vacuum gauge.

I have found my vacuum gauge very useful over the years.You can tell a lot about what is going on with the motor by watching the needle.A very inexpensive useful diagnostic tool in your toolbox.

  

A vac gauge is probably the best $20 investment I made. Most normally will measure pressure(oil, gas) as well.



An extra length of vac hose through the firewall grommet and I will occasionally run on a drive with the gage stuck on the dash. It can give you a lot of info on what is happening in the engine under load and through the throttle range. The engine is basically one big vacuum pump. I have found a lot of issues with timing and carb issues (flat spots, hesitation, rich/lean conditions transmission shift points for AT, etc) by watching what the gauge does during a drive.

I actually thought about mounting one permanently, but only have the 1 spare manifold port for a future PB booster.

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC

I have one next to my other underdash gauges.Tee into vacuum line to distributor.

  

A permanent vacuum gauge where you can see it is a great idea.  Here’s what I did on my ’55 Customline.

 

One gauge for manifold vacuum and the other gauge is used to monitor the vacuum to the distributor.  I’m using ported vacuum as the vacuum source for the distributor and at idle, there is no vacuum going to the distributor.

Lorena, Texas (South of Waco)

Thats a nice setup Ted.I am curious about the manifold vacuum gauge.What does that tell you and why would it be different than the distributor vacuum reading?In other words what would you be looking for with the manifold vacuum gauge?

  

As he told you it's for ported vacuum which is influenced by the air velocity thru the carb. The other is simply manifold vacuum.

Frank/Rebop

Bristol, In ( by Elkhart)