mcltcb

should my vacuum advance on the distributor be on timmed vacuum port or full time vacuum? thanks for any help.

Merlinhaggard

I dont know what a timmed vaccum port is but Ive always ran it to a port on the carb base. Which is a full time vaccum..???

Im sure I have a lesson to learn here..

croaker

Do a search on this forum you'll find PLENTY of input.

mcltcb

thanks for the input guys.

Glassbowtie77

Read this. http://forums.corvetteforum.com/show....php?t=1430339

rudman72

You've got to take it off the bottom of the carb. You should find a port right under the chock housing.

GEORGE TAYLOR

In Most Cases, The Vac Advance Is Tapped Into "ported" Vacuum. This Is Located Just Below The Carb. Throttle Plates.

This Is Not Done Or Used Most Of The Time On A High Performance Application (most Of The Time)
All Depends On How Much Total Advance You Want And When You Want It. You Need To Go With What Works For You Level Of Performance Gear.

norvalwilhelm

If you want vacuum advance at idle to help idle quality you need to take vacuum off the intake or base of the carb.
Taking the vacuum off the side of the carb only gives you vacuum advance while running down the road and NO help at idle.
All cars need vacuum advance and it really helps idle quality.

tommyleea

I discovered something strange yesterday while adjusting/timing my engine. 77 L48 Automatic. I read where it is better to have the distributor hooked to manifold vacuum instead of ported. The current connection to the distributor is above the throttle plates, so I assumed it was ported. Well, I connected my vacuum guage to it, and to my surprise it is reading manifold vacuum. I guess the passage itself must run down into the manifold area. It is the original Qjet built by Carter.

Tommy

pbcanney

I'm pretty sure timmed is a typo for timed (or ported, variable etc)

In the Holleys and Edelbrocks I've had over the years, you would connect the distributor to the ported vacuum. Typically this would be above the carb base, on the lower to mid body of the carb itself.

7T1vette

The primary reason for the timed or ported vacuum connections is to retard distributor timing at idle for emissions reduction. As soon as you press the accelerator, it dist. can sees manifold vacuum and operates normally. But if your engine idle is much smoother with manifold vacuum, there's no reason [other than emissions] to leave it on ported vacuum.