gruveb

And how did you set it up?

Did you time it, hook up the vac advance and then readjust the idle speed or how is it done?

kevinc

I'd say anyone running full advance all the time...even WOT...is probably too busy replacing head gaskets to respond.

But seriously, you want advance to drop off under load.

gruveb

Let me rephrase this;

Some peope run their vac advance off of the manifold or a non-tuned vac port from the carb.

That's what I'm asking about.

Vader

Some stock Pontiacs used to run full vacuum advance all the time. They were designed that way. That changed in about 1973 or 74.

gruveb

There were some people on this board who would run their cars that way, but I don't remember who.

I tried it before, but couldn't get my car running properly, but it turned out I had some problems not related to this.

I was just curious and was thinking about playing around with it....

brodyscamaro

the vacuum single for my vacuum advance HEI distributor comes from the intake manifold. it runs very well this way...

gruveb

How did you set that up?

brodyscamaro

ran a rubber hose from the intake manifold to the vacuum advance inlet.

i believe i used to have in come off the carb, but i had the car tuned by a pro and i cant really see this hurting me at all (car runs very well at all throttle positions and RPMs)

gruveb

So you don't know how he tuned it and set the idle?

Apeiron

When I set mine, I disconnect the vacuum advance and plug the port on the carb, set the timing at 3000 RPM, and then reconnect the vacuum and set the idle speed/mix.

gruveb

Set timing at 3K? hmmm, I don't have an induction type timing gun, just the "old skewl" kind.

The timing tab only goes to 12* and I've tried using those tapes, but they always fly off!

I have absolutely no idea what my total advance is, just set the initial as high as possible with pinging and roll with it.

So without an advance timing gun, sounds like I'm not equipped to try this?

Apeiron

How "old school" is your gun? You shouldn't be using anything other than an inductive pickup light with an electronic ignition.

You don't need to use a tape to set the total timing with a non-advance light. Calculate the circumference of the balancer, figure out the distance from the TDC mark to your desired timing point, measure on the balancer and put a mark there yourself. 32 degrees on a 7.5" balancer is almost exactly 2".

gruveb

Good idea.

So you set your timing at 3000 rpm at how much advance?

Then you set your idle by adjusting the air/fuel mixture along with the idle adjuster?

Apeiron

You'll need all your mechanical advance in by 3000 RPM for it to work. Has your distributor been recurved?

gruveb

Yeah, it's been worked and if I remember correctly, it has light weight springs.

I have a Crane adjustable vac canister on there too.

gruveb

I'd be able to tell if I'm at full advance at 3000 rpm by using the timing gun, accelerating the engine and watching the timing marks right? If I'm at full advance, it would remain stable.